immedi.at is an RSS to IM system.
Just load their bookmarklet to your links bar, and when you find a feed you want to monitor, click the bookmarklet and it will ask you which IM client you use, and away you go, updates by IM.
MSN alerts already has an official system set up for RSS to IM .
Does this now mean Feedburner will have to track which IM clients are reading our feeds by monitoring immedi.at somehow.
Related to this can Feedburner track which RSS to email clients are reading our feeds, like blogarithm, ERA, bot-a-blog, RMail, RSSFWD … (I know the number of subscribers who use FeedBlitz, but the others don’t let you know if people are reading your feed).