It is much more intrusive than the ads at the top of each page. Is this something we have to deal with? I hope not. Regardless what the offer might be, I will not order it, out of principle.
My opinion is... It's one thing to advertise in "acceptable" places like banners at top/bottom/side of the page, or even (yuk!) popups. But to allow ads in the forums themselves goes a bit far, in my opinion.
The message here seems to be: "We do not tolerate people spamming the board with their ads. Unless of course, they are willing to give us money. Our principles can be bought."
Unless, of course, this is someone that has somehow hijacked the board and figured out how to make themselves super moderator, place the ad, and close the threads?