A very minor change I know. You previously had to press enter when searching, and so I think this is a nice small update by the designers. In other facebook news, Mark is becoming quiet the Hollywood celeb. TMZ is now all over him (via Valleywag). Also, be on the look out for a "friend suggest" feature on facebook perhaps similar to something like last.fm's neighbors (via allfacebook). But seeing how this hasn't even made it to their dawdling "In The Works" section of the what's new page, doubt it'll be anytime soon.
