Yahoo! Messenger is a popular instant messaging client and protocol provided by Yahoo!. Yahoo! Messenger is provided free of charge and can be downloaded and used with a generic "Yahoo! ID" which also allows access to other Yahoo! services, such as Yahoo! Mail, where users can be automatically notified when they receive new email. Yahoo! offers PC to PC telephone, file transfers, webcam hosting, text messaging service, and chat rooms in various categories. For several years Yahoo! also provided a very popular service of allowing user-created customized chat rooms, however, has suspended that service since May, 2005, because of the expense relative to insufficient advertising revenues, and also because of lawsuits alleging the abuse of user-generated Yahoo! chat rooms by predators seeking contact with underage teenagers.
In addition to instant messaging features similar to those offered by ICQ and AOL Instant Messenger, it also offers (on the Windows operating system) some unique features such as: IMVironments (customizing the look of Instant Message windows) and Custom Status Messages. Another recently added feature is customized avatars. However, none of these features are available on other platforms, such as Mac OS X.
Yahoo! Messenger 2.5.3 for Mac, released in 2003, is the current stable version for Mac, and offers drastically fewer features than the Windows release. It has been reported to be quite buggy when run on the latest version of Mac OS X, and it is very primitive when compared to other messenging applications for Macintosh. However, in June of 2006, Messenger for Mac 3.0b1 was released as a beta, with a final version due later. This beta has a modernized interface when compared to the 2003 application which includes Avatars and display image viewing, BUZZ facility, and other similar features with the Yahoo! Messenger in Windows. However, it is still lacking advanced features like PC-to-PC call and address book capabilities.
Yahoo! has announced a partnership with Microsoft to join their instant messaging networks. This would make Yahoo! Messenger compatible with Microsoft's .NET Messenger Service. It would also make Microsoft's Windows Live Messenger compatible with Yahoo!'s Network. This change has taken effect. As of July 13, 2006, Yahoo! Messenger has integrated instant messaging with Windows Live Messenger users.
Unlike most instant messenger components, Yahoo! Messenger has various chat rooms for certain categories, such as interests, hobbies, featured rooms, and even current controversial isssues. Most chat rooms have more than one (ex: Rap & Hip-Hop 1, Rap & Hip-Hop 2), since the limit for each separate room is usually somewhere between 45 and 50. In chat rooms, people can enter as an alias or their usual screenname. There is no limit of how long someone can stay in a single room.
Yahoo! chat rooms are sometimes critizied. While very popular and highly-rated, Yahoo! chat rooms are known as the easiest chat rooms to install boot codes. Some people can log-on through as many screennames as possible (only using these boot codes and programs) and can crash someone's computer by IMing up to over 5,000 times. Someone however can block this by selecting "allow only messenges from people in my buddy list", but this can be an annoyance in chat rooms.