But for the folks from Mark Zuckerberg's company, such an app
could have another payoff. Literally.  It would provide Facebook
with reams of new data about not just where its users frequently
go, but where they are right now.  Facebook said it doesn't sell
its data to advertisers. But it definitely leverages the data to
help those advertisers target potential customers. It's not hard
to envision ads showing up letting users know that there's a
2-for-1 drink special right around the corner, or that the
restaurant next door has the best burger in town.  "They need to
make money on mobile, and that's what they've been pushing for
since the IPO," said Justin Lafferty, co-editor of AllFacebook,
an unofficial Facebook blog. "They're trying to build the
technology first, then maybe find out how to build ads into it,
too."  Lafferty, who wrote about this week's Bloomberg report,
said Facebook could launch a social discovery app separate from
its main mobile app -- at least at first.  "That's sort of how
Facebook usua