The most hilarious response that I've read comes from John Podhoretz, still fighting the good fight:
IF MARK FELT IS DEEP THROAT... [John Podhoretz]
...don't Woodward and Bernstein have to confirm the truth of that, like, immediately? After all, they've said they wouldn't name him because it was what he wanted, and now Felt himself is saying he was the guy in the garage. Or would W&B flinch from acknowledging that they were part of a weird FBI anti-Nixon subplot? Is this why they've kept so quiet all these years?
Translation: "The real issue here is that that the pinko FBI was out to get Nixon, not that an election-tampering, investigation-obstructing conspiracy was being orchestrated out of the Oval Office. The point is not that Richard Nixon was a cheap crook who skipped town only moments ahead of impeachment, it is that the liberal establishment always hated Nixon, just like they hate all real Amurcans! Also, I freaking can't stand smarmy Woodward and Bernstein! How I hate them for having careers and reputations to speak of! Why won't anybody listen to me? I've been on Jeopardy!"
UPDATE: Oliver Willis wins the Dr. Hunter S. Thompson Award for Cutting to the Chase for divining the real importance of the Deep Throat story:
It's not his identity.
It's that Richard Nixon will still be remembered for being a lying, dirty, scumbag crook of a president.