I just don't get it. A link is a link and trying to censor who links to what is not going to work. The AACS seems to want to control who links to the Doom 9 forum post relating to the AACS cracking attempts (direct link here) because all that's left for AACS is to try to limit people knowing how ineffective AACS is becoming. Not only will this kind of thing fail (because ultimately it draws more attention to the thing they're trying to hide) but it draws more people into the debate and these people, given the circumstances, are not going to be sympathetic to the AACS.
Here's the letter they sent to Google: