Facebook skipped the big Apple mobile event today. Robert Scoble thought Facebook and Apple would do an integration deal along the lines of how Apple is integrating Twitter, but, as I predicted yesterday, no such thing happened. Others (that would include me) thought we’d finally see a Facebook iPad app. Nothing on that front yet, either. And certainly no splashy HTML5-driven end-run around Apple’s app store. That kind of “Project Spartan” would let Facebook charge paid apps or virtual goods via Credits without cutting in Apple. An Apple-Facebook hookup would help guarantee Apple social relevance and help Facebook lock in users, but even though some of their ambitions could be mutually supportive, they don’t seem to be getting any friendlier.