I'm sorry, but there is next to zero value in an app that's sole purpose is to be a minor distraction while using another app that is itself a minor distraction.
I've had this bad feeling for a while now that facebook will be the app that we look back upon as the harbinger of the 2.0 bust.
It's a fad,(FB that is) and like all fads, from hula hoops to acid wash, it fades as fast as it grows. I honestly hope I'm wrong, but I'm starting to see more and more startups and such that provide little value for mega valuations. This isn't a good thing.
end of rant. (Sorry, it's before my coffee)