Several people have pointed out an obvious reason that conservatives might have registered tea party domains last August--Ron Paul was fond of them. To be sure, I'm not sure that timeline works out either, but it's at least as plausible as believing that some entry-level activist started plotting this months and months ago.
Meanwhile, I've spoken with Brendan Steinhauser, the chap at FreedomWorks who has helped organize the tea parties. FreedomWorks has been, as far as I can tell, completely open about their interest in furthering the tea parties, which is not surprising because they've been completely open about opposing bailouts since before Obama took office. As Brendan describes it, he and FreedomWorks were calling for demonstrations against the stimulus even before it passed, but he got the teaparty idea from Michelle Malkin's blog. FreedomWorks emailed its members and set up a website to encourage people to join in. This seems like pretty standard political organization tactics.
Overall, I'm pretty surprised that Playboy let the piece go up, left it up so long, and then took it down with no notice. To be sure, bloggers speculate all the time. But they make it clear that that's what they're doing. And when it seems clear that they've made an error (and those assertions about the Koch family now seem to, at best, require some good sourcing), bloggers update their posts. They don't vanish them and hope that no one will notice. I'm contacting Playboy's offices for comment, but not holding out all that much hope.