Thanks to Sonic for relaying this really scary screenshot of the current AIM 7 Beta:
Yes, you're seeing that right: that's an advertisement mixed in the messages themselves. Is nothing sacred anymore? I really like the notice, too: AIM is an advertising supported product. Give them credit, at least now they're owning up to it.
I can see it already: Norton Anti-Spim for AIM. Save yourself the $49.99, use BitWise instead. You know, BitWise doesn't even have to improve anymore, it gets better just because all the others keep getting worse! ;)