Well, according to a post I just read on boingboing, it has begun. The latest Charlie Rose interview with a noted Physicist by the name of Lisa Randall looks to have embedded google adwords in several places in the video.
Now I'll admit that I couldn't actually find the embedded adds. I skipped through the video to many different locations but didn't see anything, so perhaps google has already pulled them down. I trust boingboing, though, so can safely say that either those adds are there, or they were.
Either way, though, I'm sure we'll see more of this very soon.