Facebook's Real Mobile Question, Post-Instagram: Can It Challenge Apple and Google?

Facebook made a smart move today, acquiring red-hot mobile photo-sharing service Instagram for $1 billion. Not only does Facebook now own an important mobile property, but it also took its biggest threat - a thriving mobile-only social network - off the market. Brilliant.

But that's just part of a bigger, unanswered question: Can Facebook become an important mobile platform, the way Apple's iOS and Google Android have? And if so, what does that look like? How does Instagram fit in?

Facebook, as we've seen over the years, seems too ambitious to be happy just being a social network. Google Chairman Eric Schmidt didn't name it one of the tech industry's "gang of four" - along with Apple, Amazon and Google - just because it's a fun place to share status updates and connect with friends. Facebook likely has its sights set on being as important as Apple and Google are in today's mobile industry, and as powerful as Microsoft Windows once was on the desktop.

So far, Facebook is doing OK in mobile. It has more than 400 million active mobile users, which is a lot. Its main Facebook app was listed as Apple's most popular of all-time. Thousands of well-known mobile apps are "social" because of Facebook integration, so Facebook is acting as a platform of sorts there. And now, of course, it owns the mobile photo-sharing company that arguably represented its biggest threat, so that's good.

But so far, Facebook isn't exactly in a position of supreme power in mobile. It doesn't yet have an operating system that handset makers are using as the basis for phones. It doesn't own an app platform or distribution store yet. Its mobile products aren't particularly inventive or addictive. Its users could potentially go away as quickly as they arrived - see: MySpace on the web. And it doesn't make any money from mobile yet: Facebook does "not currently directly generate meaningful revenue" from mobile, it says in its IPO filing.

Expect to see more noise in these areas over the next year or so. Mobile is just too important for Facebook's future for it to sit out and cede control to Google and Apple - especially given Facebook's combative relationship with both companies, and the relative lack of success Facebook's big partner Microsoft is having in mobile.

Whether it's a proper Facebook mobile OS - forked from Android? - or a browser-based HTML5 app market, or something completely different, Facebook should start to attack the mobile platform market sometime sooner rather than later.

How does Instagram fit in? Given how quickly the deal reportedly happened - days, not weeks - it's probably too early to say. There could probably be a version of Instagram ready to go for any Facebook phone platform that eventually launches. That wasn't even something Google Android could say a week ago. Instagram may become part of the photo-sharing process in Facebook's own app. Et cetera.

And knowing how well the Instagram team has built delightful mobile products so far, it could also be a smart idea to include them on the design process of future, broader Facebook mobile products.

Big picture summary of today's news: The Instagram deal is a good one, but it's a modest step in Facebook's overall mobile plans. There's still much more, much bigger progress to make.