Facebook is the latest web 2.0 poster child to blow open the windows and unlock the doors by harnessing a platform strategy.

In a bid to become the mother-of-all social networking platforms, Facebook is opening up its APIs so that third party developers can add new features and functionality. Users will be able to assemble their own personalized collection of Facebook applications, much the way you can customize Firefox with thousands of third-party extensions.

Following in Amazon’s footsteps, Facebook has promised that developers will have significant freedom to monetize their widgets through ads and transaction revenue. Meanwhile MySpace has been muddling about — trashing third party widgets it doesn’t like and acquiring the ones it does like in typical command and control fashion.

In Wikinomics, we argued that platform strategies are all about harnessing the power of self-organization: the idea that tens of thousands of inter-operating agents can often marshal more bandwidth, more raw intelligence, and more requisite variety than the largest organization.

Other startups like flickr, 43 Things, del.icio.us, and Technorati opened up their APIs as a way to crank out new features, attract users, and scale up their businesses quickly. As Technorati’s CTO Tantek Celik put it recently: “It comes down to a question of limited time and, frankly, limited creativity. No matter how smart you are and no matter how hard you work, three or four people in a start-up—or even small companies with thirty people—can only come up with so many great ideas.”

With millions of developers who might just have the right combination of skills and insight to create something really valuable on the Facebook platform, it will be interesting to see where this goes.

Meanwhile the folks at TechCrunch are reporting some impressive stats, straight from the keynote delivered by Zuckerberg earlier today:

Facebook is growing 3% per week, which is 100,000 new users per day.

The fastest growing demographic is the 25 and up age group.

50% of registered users come back to the site every day.

Facebook is generating more than 40 billion page views per month. That’s 50 pages per user every day.

6th most trafficked site in the U.S.

More page views than eBay.

Their photos app is by far the number one photo site on the internet.

3x more people invited to events through facebook than evite.

Will Facebook’s platform strategy guarantee success? That depends on execution. One thing we do know is that winning in a world of co-creation and combinatorial innovation is all about building a loyal base of innovators that make your ecosystem stronger, more dynamic, and more expedient in creating new value for customers than the ecosystems of rivals. MySpace better get ready.