A number of third parties are now involved in providing location to mobile developers and publishers, including Skyhook, Loc-Aid and Location Labs, in addition to carriers and OEMs such as Apple, Google, Nokia and RIM. Facebook, it appears, wants to do something comparable for social on mobile devices. Last week the rumor erupted that Facebook is building a branded phone/mobile OS. Facebook denied it and invited the source of the rumor (TechCrunch) to discuss it. The resulting interview kills the branded phone rumor but confirms sweeping mobile ambtions on the part of Facebook. Facebook sees itself as a “social platform” for mobile — a social layer (not unlike location) that everyone would and could tap into to make their mobile apps more social and engaging. It wants to be deeply integrated into the fabric of mobile and as widely (horizontally) integrated as possible. Here are some verbatim Zuckerberg statements from the interview: Our strategy is very horizontal. We’re trying to build a social layer for everything. Basically we’re trying to make it so that every app everywhere can be social whether it’s on the web, or mobile, or other devices. On phones we can actually do something better. We can do a single sign-on if we do a good integration with a phone, rather than just doing something where you go to an app and it’s automatically social or having to sign into each app individually. Those are the two options on the web. Why not for mobile? Just make it so that you log into your phone once, and then everything that you do on your phone is social. [M]aybe we’ll build specific apps for iPhone and Android. And then, for something that is as important as iPhone or Android, we’ll also build integration into the operating system. For platforms that are really important, but are hard to penetrate, like iPhone, we’ll just do as much as we can. For Android, we can customize it a bit more. Other folks are going to want to work with us on specific things. But, our goal is not to build a phone that competes with the iPhone or anything like that. And this is the thing that was potentially really damaging about having that meme our there is: if all of the people that are our partners, who are the main people that we’re trying to work with to make everything social, think that we’re trying to compete with them, that makes them not want to work with us. Our goal is to make it so that we can design the best integrations in the widest variety of phones. Now, I don’t know how long it’s going to take to get the mobile environments that you see today to a state where you can build really robust social applications on top of it. So that’s the biggest driving force for us — to try to work with these folks and see how deep we can get on our own to make sure that we can build that plumbing. Our goal is to make it exist.