Ad "banners" on this site?

I'm all of a sudden noticing the ad "banners" between threads in the "Moe's Tavern" section.  Have they always been there and I'm only just now noticing them, or did something change within the past month or so?

If they've always been there, I'd say my personal, biological "ad blinders" software is working extraordinarily well!

Mike and assistant Giraffes please note: this is not a complaint.  I don't find them the least bit irritating (not that that would matter anyway): just curious to know how long it took me to notice them. I've been to some sites that literally smother a user with pop-up ads and slow site operation to a crawl: now that is irritating!