Imagine if this had happened 5-8 years ago and instead of using Twitter/FB/MySpace for the 'activity stream' it used IM statuses from all the major IM networks (ICQ, AOL, MSN, jabber etc.)
I wrote a overly complex crawler in C to grab away messages from IM networks as fast as rate limiting would allow. Then created a web frontend for viewing all of the status messages from your friends.
It was cool since in most clients at the time you needed to click on a friend and select "get info" for each status you wanted to read. Feeds for status make much more sense. However, I got tired of trying to reverse engineer the changes in various closed protocols (oscar, etc). So I did more than ponder this when I was in college, I tried it.
Bizaro world for sure but interesting to ponder.