Oh man, I was just talking about this myself. I noticed this too. Suddenly we're seeing all these new members with only a few posts to their name, all of them in the HD700 Appreciation Threads, HD700 avatars, and nothing but glowing things to say about these headphones.
One guy just posted a glowing review of the HD700 calling it "equal to the HD800" and other nonsense.... like, as one of his first posts. Gee....
Edit: I'm also not entirely sure if it's guys from Sennheiser, or if it's just a few zealous fans making sockpuppet accounts, or what...