Mplayit! [Facebook link] is a new online service that aims to let your Facebook friends share iPhone app recommendations with you -- and then take it one step further and actually let you see videos, demos, and other information before you decide to buy it via the iTunes App Store.

Now anything with iPhone and Facebook in the title is no doubt attention-grabbing, but as the App Store zooms past 100,000, discoverability is going to need fixing, if not from Apple than from a ton of independent thinkers just so something (anything) can shake out. Is Mplayit! it?

Mplayit introduces “playable discovery” for the iPhone today in its new Facebook app store and said it would add Android and Blackberry in the coming months. Rather than hunting and pecking for reviews and top lists, the Facebook page shows real “apptivity” that is going on in app stores so users can see which apps are receiving the most downloads, reviews, plays. In coming weeks, mobile users will also be able to see the “apptivity” within their social network so they can clearly see which apps their friends and family are most interested in.

Our guess is it will depend on how many popular apps they can really show off in a way that's compelling for users. If you check it out, let us know what you think.

(And really, anything that keeps Facebookers busy, and not hitting "invite all" to spam online friends with random events on other continents -- is huge.)