As of March 27, 2016, the only supported clients are the Android, i OS and web browser clients.
The legacy Windows, Mac, Linux and Solaris clients are not supported anymore, and their servers began shutting down on August 5, 2016, It turned out that the servers for the legacy clients were finally shut down sometime between the mid-morning and early afternoon hours east coast time on September 1, 2016, resulting in the legacy desktop clients no longer being able to access their buddy/contact lists.
Granted, AIM Chat was still fairly robust, and meeting people was a possibility in those chat rooms.
Yahoo, meanwhile, was plagued with issues, including everything from spambots to the last remaining real-life users kicking people from rooms with booters. Armed with an updated feature set and an array of new options, the new Yahoo Messenger launched in December 2015.
However, this doesn't actually retract the messages from the conversation; clearing the conversation just clears the history so that you can't go looking through the texts.
You'll need to upgrade to the newest version of Yahoo Messenger, as older versions are no longer supported.
Yahoo also offers PC-PC, PC-Phone and Phone-to-PC service, file transfers, webcam hosting, text messaging service, and chat rooms in various categories.
Yahoo Messenger was originally launched under the name Yahoo! In addition to instant messaging features similar to those offered by ICQ, it also offers (on Microsoft Windows) features such as: IMVironments (customizing the look of Instant Message windows, some of which include authorized themes of famous cartoons such as Garfield or Dilbert), address-book integration and Custom Status Messages.
Unsend From a Computer Note: The web and mobile version of Yahoo Messenger let you clear the conversation to remove the history from the message.
You can do this from the small (i) button at the top right of the message.