It's ridiculous. It's a text-based ad. At worst, it's a clickable image. At what point did it become okay in your minds to let advertisers run arbitrary code?
I've left ads turned on specifically on StackOverflow because 1) I want to support StackOverflow, and 2) I trust them not to run malicious ads.
I don't even care that they're running ads network-wide. But if they're going to be running these kinds of ads anywhere on the site, they're going right on the ad block list along with everyone else.