Yahoo's IM update: A Trojan horse of surprises
Found on CNet News on Saturday, 16 December 2006
Yahoo said late Friday that it has fixed a bug in its newest version of Yahoo Messenger that changed a user's mail preferences without his or her consent.
By default, the software also inserts the Yahoo Toolbar into the user's Web browser and changes the user's personalized home page and search settings to Yahoo.com. In the original download alert, people could choose to customize the installation under "options" and then uncheck these default settings. What users couldn't change, however, was that the software was adding a Yahoo Mail icon to the system tray and changed their default mail settings to Yahoo Mail.
Yahoo's Karlsten had said the engineering team was not aware of the Yahoo Mail issue and was actively working on a fix.
That's why you should use multi-protocol clients. You may not get each and every function, but it saves you resources and unwanted installs.