I don't like them. Even though my Firefox blocks the ads, it doesn't block the container the ads are put in. This means even more lost screen real estate at the top of the page, so now when I go to a thread I can't even see all of the first line of the first post in the thread.
(Yes, I know I can shrink the header that's above the ads, but I make rather heavy use of the "Show unread posts since last visit" link in it :?)
They probably wouldn't really bother me if the "Sponsored Links" box around them hadn't been there. In fact, I probably wouldn't have noticed any change at all
. I sure didn't know GameDev.net had ads until I heard some mention of them in the forums
.