Repetition is the sincerest form of mockery:
Howard Wolfson helped Bloomberg win a third term last year and is coming to work at City Hall as an adviser.
You may recall he said the same thing in 2008 before finally deciding to endorse Barack Obama for President against Hillary Clinton.
That's how early he gave up the ghost. Likely, Bloomberg calculated the economy's toll on a Presidency and decided that he'd rather someone else pick up the slack. If he runs in 2012, he'll have the benefit of four years of Obama's attempts (success or failure) to revitalize the economy.
Too, there are rumours running around that Obama is pondering just a one-term run. This is all probably just hedging his bets, freeing him to be Presidential, but you know...you can do that and still win re-election. In fact, I've long maintained that the best Presidents are those who aren't guaranteed a second term by dint of a first term blowout election (like Bill Clinton, who won only a plurality in 1992).
Still, that Bloomberg has locked up Howard Wolfson, who did a pretty good job selling Hillary Clinton, altho he could have done better, and stowing away his billions to gear up for a run has got to be disconcerting to someone like Sarah Palin, who would find it very hard to argue with Bloomberg's skills as an administrator or a candidate.