I meant to comment on this earlier but forgot about it amid the Berlin excitement. Anyway, I think the $5 million Olympic ad buy is a really big deal, and quite shrewd. Not just because Obama will get his mug out there during a traditional blackout period for presidential candidates. But because of the visual resonance.
The Olympics are billed as some lovey-dovey exercise in cross-cultural understanding. But they're basically one of the most nationalistic events on the calendar (in addition to being one of the most grotesquely commercial and geostrategically dubious). Americans tune in to see their fastest and fittest stomp all over their foreign rivals. It's basically superpower-dom by other means.
In that sense, airing Obama ads during the Olympics associates him subliminally with red-meat Americanism. You'll hear Bob Costas announce that we're up 27 over China in the medal count, or you'll see Michael Phelps getting his 17th gold medal, draped in an American flag with the Star Spangled Banner playing yet again. Then NBC will cut to an image of Obama proclaiming his own love of country. It helps Obama in all the ways I worried the Berlin speech might hurt him.
P.S. And there's a bonus here--African Americans depicted in this same patriotic light. Don't underestimate the subliminal value of seeing lots of black athletes wrapped in the flag, mouthing the words to the national anthem. As Obama might put it, it'll remind Americans that what we have in common as a lot more important than our differences. It can't hurt to be associated with that either.