Look at it another way; Is an MMO-Champion visitor employed by Blizzard?
Likelyhood is yes that they read and post in unofficial capacity, but they most certainly wouldn't let themselves be known. As far as i'm aware, none of the mods work for Blizzard (because that was once a really common question), but even if they did, they'd probably not let the rest of us know about it. Even if they did post officially, most of what they'd be saying is already available on the official forums.
I bet they do but just not in any official capacity..... they could be reading this thread right now....... <.< >.>
The true vanilla wow test is whether or not they miss Vanilla. If they do, they didn't play in Vanilla.
I think they probably keep an eye out on things here. I know they watch the front page because they have to prepare for the storm that materializes every time the data mining goes awry. Except for Zarhym's post, I doubt that you would ever know it if they did.
I'm sure there's an informal relationship between Boub and Blizz. The site is a powerful thing for the game.
That said, there's very little that ever gets posted here that doesn't turn up in one form or another there and vice versa. So I doubt that they pay THAT much attention. When something good goes on, word spreads pretty fast.