This is a little bit genius. One of the new features of FriendFeed (a Twitter-like thingie) is "fake following". That means you can friend someone but you don't see their updates. That way, it appears that you're paying attention to them when you're really not. Just like everyone does all the time in real life to maintain their sanity. Rex calls it "most important feature in the history of social networks" and I'm inclined to agree. It's one of the few new social features I've seen that makes being online buddies with someone manageable and doesn't just make being social a game or competition.
Update: Merlin Mann's proposal for a pause button is a more flexible way to accomplish the above (and more).
Any application that lets you "friend," "follow," or otherwise observe another user should include a prominent (and silent) "PAUSE" button. I think users of apps like Flickr, Twitter, Facebook, LiveJournal, Delicious, and, yes, FriendFeed, would benefit from an easy and undramatic way to take a little break from a "friend" -- without inducing the grand mal meltdown that "unfriending" causes the web's more delicately-composed publishers.
News readers too, please.
Update: See also the concept of artificial attention.