Not sure if this should be a comment or answer...
I participate on cooking.SE a bit, so I recognize that logo as another SE site. But since I don't pay attention to any other SE sites, I find some of their ads to be intrusive, e.g. Area51 and Gaming.
I know the idea of the ads is to get people from one SE site to be aware of others that might be of interest, but I think it's a weakness of SE, Inc.'s business model to think that, say, professional sysadmins will also have expert-level advice to give on cooking or biking or car repair or whatever. (Obviously there are likely to be cross-site experts for some pairings.)
Maybe if they put any and all SE ads inside a less-annoying StackExchange frame, with the site-specific logo much smaller.