As an addendum to Tom's post, the Romney campaign put up this video on its YouTube page showing John McCain endorsing Romney for governor in 2002 (and employing some very strong adjectives in the process):

I guess this is supposed to show that McCain used to "heart" Romney back then, but doesn't now out of political ambition. (Flip-flop!) But it's a little weak as far as "YouTube Moments" go, since folks probably expect Republicans to endorse Republicans.

More videos in the Vlog.