Yahoo! Messenger - Wikipedia
https://en.wikipedia.org/wiki/Yahoo!_MessengerYahoo! Messenger (sometimes abbreviated Y!M) was an advertisement-supported instant messaging client and associated protocol provided by Yahoo!. Yahoo! Messenger was provided free of charge and could be downloaded and used with a generic "Yahoo ID" which also allowed access to other Yahoo! services, such as Yahoo! Mail. The service also offered VoIP, file transfers, web…