Building a cross-platform application took on new meaning at the end of last week with the launch of Facebook Platform. In a sense what Facebook has accomplished is a tantamount exhibition of Tim Orielly's notion of "The Web As Platform", coupled with a brilliant competitive lock on, "Data...the Intel Inside". All of that is to be expected, thought they still deserve kudos for execution.

What's incredible is that Facebook has accomplished to created a microcosm that is per unit more valuable than the macrocosm it exists in. MySpace did something similar with the comment wall. It created a less functional microcosm of the the email macrocosm. Did you hear me? Less functional! The result was an application with razor focus on getting users to use it for the one thing it did do well...keeping friend's upto date on each other's lives.

Case in point is iLike's Facebook application which provides a handful of the features of iLike.com and is restricted UI wise by the limits of the Facebook API. It's growing faster and has more user engagement than the main site. Why? Simply because the iLike team is freed from building out a social network and can focus on building a music application. Moreover, Facebooks social functions are far more refined than iLike.com's (not surprisingly). In the end it is an application of basic competitive advantage theory: Facebook focuses on their strengths in the form of the social graph, iLike (and any aspiring Facebook developer) can focus on their social application.