The more I think about it, the more I think the PepsiCo/Scienceblogs episode was a great opportunity missed.
Yes, like many I'm concerned about the corporate infestation of government and of society. But the thing is, corporations like PepsiCo go to great lengths to isolate themselves and minimize (if not eliminate entirely) meaningful rebuttal.
Here was a corporation about to initiate daily conversations (and that's what blogs are) with readers who can write back for all to see. Commenters, other bloggers, and journalists could evaluate and counter PepsiCo's claims in near-real time, in the way only the Web/blogosphere can accomplish. They could cite the scientific literature to show how/if they were wrong, unlike any other medium possible.
Instead of merely be passively bombarded by PepsiCo's innumerable television commercials, here you could talk back and call their bluff, if appropriate. Readers could point out their factual and scientific errors, or call their point of view into question, or question their entire foundation.
Heck, done right, PepsiCo would have themselves withdrawn their blog in a few weeks, shocked at the implications of truly free speech.
Instead they are hounded out before they even said anything, and prominent science writers quit in a huff because sharing a forum with such cretins was beneath them.