Yahoo! Messenger is my favorite instant messaging client because I can be visible to those I choose to, when I choose to.
I’ve found only one new thing worth noting in the latest version: the Yahoo! Messenger Pingbox. It will allow you to “chat privately with visitors on your social network profiles, blog, or website through Yahoo! Messenger.” Compatible with MySpace, Friendster, hi5, Blogger, Live Spaces, LiveJournal, and Xanga.