Andy Beal and Jarrod Hunt reveal tactics Yahoo is using to get your preferences to switch to Yahoo. If you upgrade to Yahoo Messenger it will also try to download and install IE7 (ewww), and then it switches the browser default from FireFox et al to IE7 and search engine settings to use Yahoo.
Who in the world is running Yahoo? This is NOT good for Yahoo! and there is going to be a backlash if this isn’t confronted today (that’s today, not tomorrow).