WeChat is a free application launched by Tencent on January 21, 2011 [1] to provide instant messaging services for smart terminals, and was built by the product team at Tencent's Guangzhou Research and Development Center [2] led by Bruce Zhang. WeChat supports the rapid sending of free (with a small amount of network traffic) voice messages, videos, pictures and text over the network across telecommunication carriers and operating system platforms, as well as the use of streaming content material and location-based social plug-ins such as "Shake", "Circle of Friends", "Wave", "Wave of Life", and "Wave of the World". Circle of Friends", "Public Platform", "Voice Notepad" and other service plug-ins.

As of the second quarter of 2016, WeChat has covered more than 94% of smartphones in China, with 806 million monthly active users,[3] covering more than 200 countries and over 20 languages[4]. In addition, the total number of WeChat public accounts across brands has exceeded 8 million, the number of mobile apps docked exceeds 85,000, advertising revenue has increased to RMB 3.679 billion [3], and WeChat Pay users have reached around 400 million [4].

WeChat provides a public platform, a circle of friends, and push messages, allowing users to add friends and follow the public platform through "Shake", "Search Number", "Nearby People", and scanning QR codes. Users can add friends and pay attention to the public platform through "shake", "search number", "nearby people", scanning QR code, while WeChat will share the content to friends and share the wonderful content that users see to WeChat circle of friends.

In December 2020, WeChat was updated to version 7.0.20 for iOS, with the addition of "WeChat Beans" on the profile page [5]. On January 21, 2021, WeChat was updated to version 8.0 [6]. In July 2021, in the latest version 8.0.8, WeChat was updated to version 8.0.8, allowing users not only to log in to mobile phones, but also to PCs and other public platforms. Not only can you log in to cell phones and PC/Mac devices at the same time, but also added a simultaneous login function for tablet devices, which means that tablet devices are already at parity with cell phones and computers in WeChat's logic of use, and the number of devices that users can log in to at the same time has reached as many as three [110]. November 7, 2021 [11]. WeChat user complaints page new "fans without bottom line star behavior" item

WeChat by Shenzhen Tencent Holdings Limited (Tencent Holdings Limited) in October 2010 planning to start by the Tencent Guangzhou R & D Center product team to build . The team, led by team manager Zhang Xiaolong, has successfully developed Internet projects such as Foxmail and QQ mailboxes. Tencent's president Ma Huateng identified the name of the product as "WeChat" in the product planning email.

2011

On January 17, 2011, a Beijing-based cultural communication company applied to register the WeChat trademark, while Tencent's WeChat trademark was filed for registration on January 24, 2011, just one week late.

On January 21, 2011, WeChat released its 1.0 beta version for iPhone users. This version supported importing existing contact information via QQ numbers, but only had simple features such as instant messaging, sharing photos and changing avatars [9].

In the subsequent 1.1, 1.2, and 1.3 beta versions, WeChat gradually added support for reading cell phone address books, interoperability with Tencent's microblogging private messaging, and multi-conversation support, and by the end of April 2011 Tencent's WeChat had gained 4.5 million registered users [9].

On May 10, 2011, WeChat released version 2.0, which added a Talkbox-like voice messaging feature that allowed WeChat's user base to grow significantly for the first time.

In August 2011, WeChat added a stranger dating feature called "View Nearby People," which reached 15 million users. By the end of 2011, WeChat had more than 50 million users.

On October 1, 2011, WeChat released version 3.0, which added the "Shake" and "Drift Bottle" features, added support for the Traditional Chinese language interface, and added the ability to bind cell phone numbers for users in Hong Kong, Macao, Taiwan, the U.S., and Japan [9].

2012

In March 2012, the number of WeChat users passed the 100 million mark, and on April 19, WeChat released version 4.0, which added features like Path and Drift Bottle. This version added a photo album feature similar to Path and Instagram, and the ability to share photo albums with friends [9].

In April 2012, Tencent began its attempt to take WeChat to the international market, renaming the English version of WeChat 4.0 "Wechat" for the purpose of its Europeanization, and later launching multi-language support [9].

On July 19, 2012, WeChat version 4.2 added a video chat plugin and released a web-based WeChat interface [9].

On September 5, 2012, WeChat version 4.3 added the Shake to Transfer feature, which makes it easy to transfer pictures from your computer to your phone. This version also added a voice search function and support for unbundling cell phone numbers and QQ numbers, further enhancing users' control over their personal information [9].

On September 17, 2012, Tencent's WeChat team announced that the number of registered WeChat users had surpassed 200 million [10].

2013

Late on the night of January 15, 2013, Tencent's WeChat team announced on Weibo that the number of WeChat users had surpassed 300 million, making it the world's most downloaded and most used communications software, with a reach that extends across mainland China, Hong Kong, Taiwan, and Southeast Asia, as well as to overseas Chinese congregations and a handful of Westerners [9].

On February 5, 2013, WeChat released version 4.5 of WeChat. This version supports real-time intercom and multi-person real-time voice chat, and further enriches the functions of "shake" and QR code, and supports searching, saving and migrating chat records. Meanwhile, WeChat 4.5 also added voice reminders and the ability to navigate based on the location sent by the other party [9] [11] .

On April 11, 2013, Tencent's WeChat team issued an official statement to some users via WeChat, saying that "WeChat is going to charge users" was a malicious rumor and emphasizing that WeChat would never charge users [12].

At 7:30 a.m. on July 22, 2013, a large number of users reported that WeChat was experiencing a full-blown outage, including the inability to send out WeChat messages, the inability to refresh the circle of friends, the inability to log in to the public account platform, and the inability to connect to the WeChat web page. The incident has been disturbed until about 2:00 p.m. before the WeChat development team within its Tencent microblogging. It announced that WeChat could be used again, but some users still left messages saying that some of the functions had not been restored after entering WeChat, or that they had not been able to connect at all.

On August 5, 2013, WeChat 5.0 for ios went live, adding an emoji store and a game center, and a new upgrade of the sweep (313 for short) function, which allows you to sweep street scenes, barcodes, QR codes, word translations, and covers, and on August 9 of the same year, WeChat 5.0 for Android went live.

On August 15, 2013, WeChat's overseas version (WeChat) registered users exceeded 100 million, with 30 million new users in a month.

October 13, 2013, Citywide Search aspires to help individuals or enterprises who are not technically savvy to build their own interface programs, so that individuals or enterprises who are not technically savvy at all can have powerful functions through simple configuration. Enterprises can use Citywide Search to realize the function of intelligent customer service robots at a low cost, shopkeepers can easily realize the association and interaction of store products and fans, and will soon provide powerful management function modules for WeChat local number operation and maintenance personnel of local operation and maintenance.

October 19, 2013, WeChat LBS graphic response is set by the merchant store location, the user submits the current location, you can find the nearest merchant store, and one-key navigation, one-key dialing, if the store currently has the activities carried out (such as: coupons, scratch cards), you can also show the activities.

On October 24, 2013, Tencent's WeChat had more than 600 million users and 100 million daily active users.

On December 31, 2013, WeChat 5.0 for Windows Phone went live , adding an emoji store, binding bank cards, favorites feature, binding email, sharing messages to friends, and more.

2014

On January 4, 2014, WeChat added the taxi function provided by Tic-Tac to the product [13].

On January 28, 2014, WeChat was upgraded to version 5.2 with a new interface for Android.

March 2014: Opened WeChat Pay function.

March 24, 2014, computer housekeeper hand in hand with wechat on-line chat record backup function.

August 28, 2014, WeChat Pay officially announced the "WeChat Smart Life" industry-wide solution. It is based on WeChat Public Number and WeChat Pay, which helps traditional industries to "transplant" their original business model to the WeChat platform.

The closed-loop mobile Internet business solutions provided by WeChat include service capabilities such as mobile e-commerce entry, user identification, data analysis, payment and settlement, customer relationship maintenance, after-sales service and rights protection, and social promotion. This also signals that WeChat is once again increasing the pace of commercialization and opening up to provide partners with the ability to connect and boost the mobile Internet transformation of business models for enterprise users.

By providing partners with the ability to "connect everything", WeChat is forming a new "smart" lifestyle. It has already penetrated into the following traditional industries, such as WeChat Taxi, WeChat Electricity, WeChat Shopping, WeChat Healthcare and WeChat Hotel. It provides standard solutions for dozens of industries such as medical, hotel, retail, department store, catering, ticketing, express delivery, university, e-commerce, and people's livelihood, etc. [14] .

2015

On January 21, 2015, WeChat was the first to launch version 6.1 on the App Store, and the new version added "send WeChat red envelopes from the attachment bar", "customized emoticons won't be lost when you change your phone", "you can change your phone", and "customized emoticons will not be lost when you change your phone". The new version adds three major features: "send WeChat red envelopes from the attachment bar", "customized emoticons won't be lost when you change your phone", and "you can search for the contents of your circle of friends and nearby restaurants". There's also an opening slideshow after installation - a count of the "Likes sent" and "Likes received" you've made over the past year.

2016

January 11, 2016, the father of WeChat, Zhang Xiaolong, after many years of public appearance, explained the four values of WeChat. Bruce Zhang pointed out that more and more products are made through the public number, because the cost of development, user acquisition and dissemination is lower here. The service number split out does not provide a better service, so WeChat is internally working on a new form called 'WeChat small program' [15].

From March 1, 2016, WeChat Pay stopped charging handling fees for the transfer function. On March 10, WeChat officially announced the details of "Enterprise WeChat" for the first time, and released the Android version on April 18 through AppBao.In August, WeChat and Alipay were awarded the first payment licenses in Hong Kong [17].

September 21, 2016, WeChat small program officially opened internal testing. Under the WeChat ecosystem, the WeChat small program, which is at your fingertips and ready to use, has attracted widespread attention. Tencent Cloud officially launched the WeChat small program solution, providing a technical solution for small programs on cloud servers [18].

2017

At 0:00 on January 9, 2017, the much-anticipated first batch of WeChat's small programs were officially launched in a low-profile manner, allowing users to experience a wide variety of services provided by small programs [19].

In February 2017, Brand Finance released its 2017 list of the top 500 global brands, and WeChat ranked 100th [20].

On the evening of March 23, 2017, WeChat officials quietly launched the "WeChat Index" function, which Tencent defines as a mobile index provided by WeChat officials based on WeChat's big data analysis [21].

April 19, 2017, WeChat announced that, due to the introduction of Apple's new rules, the in-app payment rules have changed, the iOS version of the WeChat public platform and emoji platform appreciation function from the same day 17:00 onwards was shut down, Android and other versions of the WeChat appreciation function is not affected. In addition, Tencent sources said that the red envelope is not in this category, will not be affected.

The reason for WeChat's adjustment of the appreciation function of the public platform and emoji platform is that Apple updated its 3.1.1 clause on June 13, 2016, which more strictly requires that the App shall not contain buttons, external links or other call-to-action phrases that guide customers to make purchases using non-IAP mechanisms.

WeChat also said that after the appreciation function is closed, WeChat public number operators can display QR codes in their articles and get support through personal transfers. In order to protect the user's funds, such transfer of funds will take the T + 7 settlement cycle, such as the generation of funds frozen or refunded, you can view the relevant flow in the background of the WeChat public platform [22].

On May 4, 2017, WeChat Pay announced its official entry into the United States together with CITCON. After WeChat Pay officially entered the United States, people going to the United States can enjoy the convenience of cashless payment in the United States. Through WeChat Pay, clothing, food, housing and transportation in the United States can be settled directly in RMB [23] .

Since the morning of May 5, 2017, some WeChat users in Russia have been experiencing restrictions on their use, and the web version of the service is unavailable. The Russian government asked the service providers to provide information on business registration in the country where they are located, the address of their servers, and a description of the software's functionality. The Russian side assured that the blocking of WeChat would be lifted after the provision of the aforementioned information [24].

On May 18, 2017, WeChat ushered in an update that added the 'WeChat Labs' feature. Currently, the enabled experiments are 'Take a look' and 'Search' [25].

On the afternoon of August 21, 2017, WeChat had a large-scale failure, and no other app content could be shared to friends and the circle of friends; the WeChat transfer function was also temporarily disabled, and the red envelope function was normal.

For four days from 17:00 to 17:00 on September 25-28, 2017, the picture of the Earth displayed on the mobile WeChat startup page will also be replaced with an imaging map of Fengyun 4 from the previous NASA (National Aeronautics and Space Administration) first complete photo of the Earth made public around the world. This is the first time the WeChat launch page has been changed in six years [26].

On November 8, 2017, WeChat was named to the TOP 30 list of business cases in China [27].

On December 28, 2017, WeChat's updated version 6.6.1 suddenly opened up mini-games, and the WeChat launch page highlighted the mini-game 'Jump One Jump' [28].

2018

On January 10, 2018, on the occasion of the nation's 32nd 110 Awareness Day, a new type of live interactive alarm method - "@110" - jointly developed by the Yantai Public Security Bureau and Tencent, was national debut online [29].

On January 31, 2018, WeChat released a new version 6.6.2 for iOS, which supports one-key switching of logins between two accounts, as well as a discovery page management feature [30].

On February 9, 2018, the WeChat team announced that it adheres to zero tolerance for online gambling, and that the WeChat team, through user-reported data and after verification and forensics,*** counted more than 2,300 gambling-related WeChat groups for the restriction of group functions, and more than 30,000 accounts for the restriction of function use or restriction of login, and other step-by-step penalties [31].

On the evening of February 10, 2018, the WeChat team issued a heavy announcement [32] in response to malicious violations and confrontational behavior in the WeChat circle of friends.

In February 2018, the number of WeChat's global monthly user activity exceeded the 1 billion mark for the first time [33].

April 1, 2018, Alipay and WeChat static barcode payment, daily limit of 500 yuan [34].

From April 9, 2018, the Tianjin Municipal Market Supervision Commission in the China (Tianjin) Pilot Free Trade Zone Dongjiang Port Area, and the Jiangsu Provincial Administration for Industry and Commerce in Nanjing, Zhenjiang, Suqian, Lianyungang, four cities, at the same time to start the "enterprise through the WeChat small program to download and use the electronic business license" service [35].

In May 2018, in order to protect users' privacy and optimize the experience of WeChat's external links, the WeChat team further upgraded the rules related to the "WeChat External Link Content Management Specification", and the new rules will officially come into effect from May 29th [36].

On August 7, 2018, WeChat, in order to ensure the healthy operation of the platform, the article reading data in the background of the public number will exclude false data brought by machines and other unnatural reading [37].

September 30, 2018, from now until the end of December, users can participate in the Shake and Play campaign to have a chance to get a free order on the spot or WeChat Pay in-store red packets when they successfully use WeChat Pay at WeChat Pay partner stores in South Korea, Japan, Singapore, Thailand, Australia, and New Zealand [38].

From November 30, 2018, WeChat and temporarily took down its drift bottle service to specifically clean up pornographic content [39].

2019

January 7, 2019, Tencent cloud vice president Chen Ping said at the IPv6 (Internet Protocol Version 6, the sixth version of the Internet Protocol) Zhilian upgrading conference, Tencent cloud will realize the IPv6 in all in 2019, both the whole ecological promotion of IPv6 strategy [40].

On October 10, 2019, WeChat Pay stated that it does not support virtual currency transactions [41].

October 2019, WeChat launched the function of "transferring money via cell phone number", which allows others to remotely transfer money to WeChat Zero Money without adding friends [42].

On October 18, 2019, WeChat announced that it had upgraded its Code of Content Management for WeChat External Links, specifying new types of violations. The new rules were officially enforced from October 28 [43] .

In November 2019, WeChat began to gray-scale test the new "related reading" function at the bottom of public number articles, that is, the "related reading" module will appear at the bottom of some articles sent by the public number group, recommending extended reading content related to that article The "Related Reads" module will appear at the bottom of some of the articles sent by the public number, recommending extended reading content related to the article to help users understand related events or content they may be interested in.

2020

On March 21, 2020, WeChat's iOS 7.0.12 version went live, offering the ability to use WeChat in dark mode [45].

On the evening of June 3, 2020, WeChat finally went live with the WeChat Payment Score feature [46].

June 5, 2020 news, Android users update to the latest version of WeChat, you can modify the micro-signal, the entrance is in the "me" - "personal information" - "micro-signal". The portal is at "Me"-"Personal Information"-"Weixin", and eligible users can modify their Weixin signals once a year [47].

On June 17, 2020, WeChat launched the "Take a Shot" feature [48].

On July 26, 2020, WeChat stopped serving users in India. The affected WeChat accounts were registered with local Indian numbers, while those registered with Chinese cell phone numbers can still use it normally. All indications are that WeChat's deactivation of WeChat for users with Indian cell phone numbers should be a technical measure adopted on its own initiative to avoid legal risks. When the account is logged out, the user receives a message from the WeChat team that reads, "According to Indian law, we are currently unable to provide WeChat services to you. We value each and every one of our users and data security and privacy is of utmost importance to us. We are engaging with the relevant authorities and hope to be able to resume the service in the future [49]. "

On September 9, 2020, WeChat Search launched the "fingertip search" function [50].

On September 18, 2020, the U.S. Department of Commerce posted on its official website that in response to an executive order signed by President Trump on August 6, 2020, the U.S. Department of Commerce announced that it was prohibiting transactions related to the mobile applications (apps) WeChat and TikTok in order to safeguard U.S. national security, and that TikTok and WeChat would be taken off the shelves [51] in the United States starting September 20 [52] . territory to be taken off the shelves [51].

In December 2020, WeChat on iOS was updated to version 7.0.20, with the addition of "WeChat Beans" on the profile page. It is reported that "WeChat Beans" are props used to pay for virtual items in WeChat, and can be used to buy virtual gifts in live video broadcasts [5].

2021

In the afternoon of January 21, 2021, WeChat iOS carried out a major update, WeChat V8.0.0 on-line, updated about 400M, WeChat emoticons to realize the dynamic playback, the 8.0 version of the on-line a series of new version of the emoticons, which is the most highlights of the "bomb" and "Fireworks" [52]. Updated the nearby live broadcasts of video numbers, which can be categorized to find the live broadcasts that users are interested in. Added a new status bar underneath Me - Weibo, where you can edit your status. Status is divided into three categories: Mood and Thoughts, Work and Study, and Activities. The status can truly show the current situation of the user, for example, set "busy", "fishing" and so on. The same person who set "Busy" can also see the status of his/her friends. In the latest version 8.0 of WeChat, the floating window on the home page has been hidden in the upper left corner of the home page to ensure the simplicity of the home page. Clicking on the floating window in the upper-left corner of the home page, the left side of the home page will display unread articles in the form of tabs, and users can continue reading by clicking on the corresponding articles [53] .

On April 14, 2021, WeChat went live with a small feature, "Public QR Code to Public Business Card in One Click" [106].

On May 28, 2021, WeChat Circle released an announcement stating that it would be officially discontinued on December 28, 2021, due to the adjustment of business development direction [107].

On July 2, 2021, WeChat 8.0.7 for Android was released. [109] In the newly released version 8.0.8, WeChat not only allows simultaneous logins for mobile and PC/Mac devices, but also adds simultaneous logins for tablet devices. [110]

On September 17, 2021, Tencent released an adjustment statement for the "WeChat External Link Content Management Specification," stating that users upgrading the latest version of WeChat could access external links in one-on-one chat scenarios. [113]

Care Mode

Care Mode [114]

September 28, 2021, recently issued a new version of WeChat formally launched the "care mode". Compared to the normal mode, WeChat Care Mode has larger and clearer text, stronger and more recognizable colors, and larger and easier-to-use buttons, which helps to improve the convenience of using WeChat for the elderly, visually impaired groups, and other people. [

On October 11, 2021, WeChat released iOS 8.0.15, upgrading WeChat's Teen Mode with a new feature called "Guardian Authorization". Parents can use this feature to manage their children's use of WeChat. With this feature on, teens can remotely apply for guardian authorization to access public number articles, applets, links, and extend the use of video numbers, and the guardian can remotely authorize the application through their personal WeChat account.[115] With this feature, the guardian can authorize the application remotely through their personal WeChat account. [115] With this feature guardians can decide what to show their teenagers and for how long. [118]

In October 2021, WeChat released a statement saying that WeChat Pay has realized offline barcode mutual recognition and mutual scanning with UnionPay Cloud Flash Pay, UnionPay Cloud Flash Pay fully supports Q Coin, QQ Music and Tencent Video top-up services, and WeChat Small Programs also gradually support Cloud Flash Pay payments. [119]

On November 7, 2021, WeChat added a new item on its user complaints page called "Fans Chasing Stars Without a Bottom Line," which allows users to complain about individual accounts and group chat members. [120]

On November 15, 2021, WeChat launched its own input method. [125]

In 2021, WeChat released an update to the WeChat Content Management Standards for External Links: external links will be directly accessible in peer-to-peer chat scenarios; and the function of direct access to e-commerce external links will be opened up on a trial basis in group chat scenarios. [127]

On November 30, 2021, WeChat macOS version 3.2.2 was released, and this update mainly supported two folding group chat functions and fixed some known issues. [130]

In December 2021, the WeChat team released the "WeChat Compliance Guidelines on Regulating the Release and Distribution of Out-of-School Training Content" on the WeChat public platform. Among other things, it requires that no promotional or inducing content for primary and secondary school students (including kindergarten preschoolers) in disciplines and non-discipline-based out-of-school training organizations be published on WeChat, as well as that WeChat platforms not be used for primary and secondary school students (including kindergarten preschoolers) to illegally carry out disciplines and non-discipline-based out-of-school training. [131]

In 2021, WeChat's PC client, after upgrading to the latest version, including the Windows and macOS versions, already supports automatic login to that device, with the option of logging in on commonly used devices without the need for cell phone confirmation. WeChat now supports logging in to computers, tablets, watches, and other devices at the same time. [132]

In December 2021, Galaxy Kirin Desktop OS V10 including V10 SP1 completed migration adaptation with Tencent's native WeChat and was available on the Kirin Store. [134]

2022

On January 6, 2022, the 2022 WeChat Open Class Pro was held in Guangzhou, where WeChat Open Class instructor Zeng Ming revealed that WeChat's small programs in 2021 had a daily activity of more than 450 million, with the average number of daily uses increasing by 32% compared to 2020, and active small programs increasing by 41%. [136]

January 2022 , the Digital RMB App was upgraded and updated, the WeChat Bank (WeChat Pay) Digital RMB wallet went live, and Tencent accessed the Digital RMB to begin providing services. [137]

On January 15, 2022, WeChat iOS was updated to version 8.0.17, which added the much-anticipated "voice pause" feature, supporting voice pause and resume playback. [139] In the face of a long voice, long-pressing during playback can pause the voice, and the "Continue Playing" button will appear on the right side, and the voice will continue to play when you click on the button. In general, this avoids the situation where someone interrupts you and you can't pause your voice, and then you have to listen to it again. [141]

In January 2022, WeChat for Mac 3.3.0 was updated to include a new video number feature, in addition to the ability to search for micro signals to add friends. [142]

January 2022, WeChat for iOS receives version 8.0.17 update. [143]

On January 20, 2022, WeChat officially announced that the Ministry of Industry and Information Technology (MIIT) "Special Action on Ageing and Accessibility Improvement of Internet Applications" had released the first batch of more than 200 websites and apps that had passed the ageing and accessibility assessment, and that both WeChat and WeChat Pay (which is built into the WeChat App) were the first to pass the assessment. Both WeChat and WeChat Pay (built into the WeChat App) were among the first to pass the evaluation. [145]

In January 2022, iOS WeChat version 8.0.18 was officially updated to allow 20 images to be selected for the WeChat Friend Circle. [147] Modified the ringtone interface from the original list form to a video stream form. WeChat iOS version of "I" - "Payment", has been fully changed to "Services" [148].

On February 14, 2022, WeChat updated its "WeChat Car Edition" introduction page to show that WeChat Car Edition has access to 15 automakers, including Audi, BMW, Beijing, Chang'an, and Great Wall. [

In February 2022, WeChat received a major upgrade to version 8.0.18 of the iOS version, which supports sending more than 9 images to a circle of friends. When the user selects more than 9 pictures, it will show to make a new video. In addition, the ringtone modification interface has been changed from a list to a video stream. The "Payment" in the "Me" page has been changed to "Service". [154]

February 2022, the WeChat App now supports sending 4K raw video with almost no compression. [156]

On March 4, 2022, the WeChat Payment platform released the Notice on Further Reducing Payment Handling Fees for Small and Micro Merchants for customers. The notice stated that from September 1, 2021, until September 30, 2024, payment handling fee discounts will be applied to small and micro merchants that meet the criteria. [158]

As of March 15, 2022, WeChat has launched an algorithm shutdown button that allows users to turn off "personalized recommendations" with one click in the background. [160]

On March 25, 2022, WeChat's Android platform received the 8.0.21 beta update. The official changelog is optimized for some known issues. Web version of the file transfer assistant after login to open the "file transfer assistant"; status support double-click to like; chat image search function, pictures can also be "search a search"