Yahoo Messenger hasn't been a big deal for years, but it was absolutely massive at one point in time. Yahoo user IDs will continue to work with other services (such as Yahoo Mail). Oauth, the new parent company of Yahoo and AOL, sold Flickr recently to SmugMug, and shut down AOL Messenger AIM back in 2017.
"After July 17, 2018, you won't be able to access or sign in to Yahoo Messenger".
The new version of Yahoo Messenger was launched in December 2015, and phased out the original Messenger app in August the following year. As users migrated away from dedicated chat apps to social networks and mobile messaging, however, the market for Messenger dried up.
People who want an archive of their Yahoo Messaging texts can visit a special website where they can download a history of their messages, but they only have six months to do so. At the moment, there is no direct replacement for Yahoo Messenger, but users are being advised that they can request an invite for the beta version of the invite-only group messaging app Yahoo Squirrel.
After July 17, users won't be able to log into the Yahoo Messenger app on either their phone or computer.
"We know we have many loyal fans who have used Yahoo!"
One Twitter user said they even met their wife while using Yahoo Messenger. That can be achieved through a specific downloader request site.
After July 17, the Yahoo Messenger app will cease to function.