Facebook’s embedded option
cdixon.org
cdixon.org
Search is obviously a big, big money spinner and Facebook now has enough people on who keep it open during the day that they could get a large amount of traffic from people who aren't as interested in the different ways search results can be generated and aren't that fussed. With their database of places, events, venues and so on they'd probably have very interesting results for a specific set of information, and I imagine being able to get into that result set would be worth a decent amount of some groups. It's straightforward business but with some serious amount of backend work going, I imagine if we start seeing Facebook staff up rapidly it might signal they're going for it.
I said payments down the stack, I'll quickly justify. Facebook's biggest problem right now is getting people to trust them as a mechanism, they've had a few scandals that have trickled into the mainstream media from privacy options, companies forcing handover of login details and so on, which erodes the trust-base of users slightly which isn't a great start for a payment service.
Having payment details and a verified identity would massively increase the value of Facebook's user profiles and the low-friction payment they could offer would be an invaluable asset.