Everyone's still talking about Henry Blodget's facile guess on his Internet Outsider blog that Microsoft might offer $6 billion for Facebook, the social network of the moment. And Facebook investor Jim Breyer, the Accel Partners venture capitalist who's on Facebook's board, tried to stoke hopes for such an outsized valuation by casually mentioning at Fortune's iMeme conference that Facebook was on track to do $100 million in revenues and turn an operating profit, by some financial measures, this year. But you shouldn't buy Blodget's musings, or Breyer's shilling, for a moment. Here's why.