If it's true, it's damned interesting, at least to me personally. From what I've seen of him, Bloomberg appeals to me on a gut level more than most of the major-party candidates, maybe more than any except Obama. And from a policy perspective, he's *way* closer to me than any of the rest of the mob seeking the Presidency.
Of course, the interesting question is whether he stands a chance, and that's a remarkably complicated question. Normally, third-party bids are Doomed Doomed Doomed: Perot came closest of anyone in recent decades, and he was still a fairly distant third. That said, Bloomberg has a lot to say for him. He's got enough money that he doesn't need a major party's funding (as one pundit put it, he could fund a $100 million campaign and not notice the money spent). His indecisive relationship to the major parties mirrors that of much of the electorate. He's a true Beltway Outsider, that coveted title that not many of the existing candidates can honestly claim -- he's basically got all of Romney's strengths and none of his weaknesses. He's proven himself to be quite competent, and willing to take intelligent risks. And the fractured state of both parties (and the moderate discontent with the candidates on offer) leaves an interesting and unusual opportunity for him.
Really, though, the political bookmaking depends entirely on who gets nominated from the Big Two, although it's complex no matter how you slice it. If both parties nominate from their extremes (say, Thompson vs. Edwards), the hardcore of both parties will be happy, but the broad center will be looking for better options, and Bloomberg could pick up much of that. OTOH, a lot of voters on both sides will be extremely nervous that a vote for the independent will make it easier for The Other Side to win.
On the flip side, if both parties nominate centrists (for instance, the Subway Series of Giuliani vs. Clinton), the extremes of both will basically sit on their hands and stay home. (Or vote for fringe extreme parties that stand no chance.) Centrists on both sides will have less driving them away from their home parties, but on the other hand will have less to lose if they vote for the independent, since The Other Candidate isn't quite as bad relatively speaking.
Possibly best for Bloomberg would be if one side went extreme and the other didn't: the centrists in the extreme party would be driven to look for an alternative that was more palatable than the opposition, and Bloomberg would make a fine Lesser Evil. Add to that some folks from the less-extreme party who see the extreme side as likely to go down in flames (and therefore willing to chance it), and he'd have a shot.
All that said, I probably would put his chances at no more than 20% under the best of circumstances: the American two-party system is *deeply* entrenched, and it's hard to buck that system. He'd have to convince people on both sides not only that he's the best candidate, but that a vote for him isn't wasted; recent history makes that a hard sell.
So: opinions? Should he run, or shouldn't he? Do you like him, or not? For the moment, this is nothing more than an interesting speculative side-show; we'll see if it turns into something real. But it's intriguing...