Ad Age says now that we have a black president, the White House will now be the place from which urban trends emanate. I'm not kidding. What the article clearly demonstrates is that the writer has no concept of how trendspotting works or even what constitutes a trend. The examples he gives: basketball, the fist bump, and eating at home. For at least the first two, you could easily argue that these are trends, and that they did start with black America and then trickle out into the mainstream... in the 80s.
Okay, the handshake thing is a bit more complicated, since the preferred gesture du jour changes from time to time (remember the hi-five, pound, snap?), but again, white people have been tuned into black hand movements for at least a few decades.
What they should have said: A president who is more in tune with what's going on in the country will have an easier time influencing our attitudes and behaviors than the "old white man" archetype that's been in the chair from day one. But to suggest that the guy running the free world is somehow in tune with the latest street trends — or that those of us who are tapped into that sort of thing are going to suddenly look to the most mainstream voice in the country — is just plain ignorant.