Brad Ward reported yesterday on his Squaredpeg blog that he's uncovered what looks like rings of people who are creating groups for incoming freshmen classes on Facebook (or getting admin privileges on these groups) for questionable purposes. These people are not actually applying to or planning to attend these schools. They may be developing networks that will allow them to easily target students with marketing campaigns.
Schools need to be aware that their Facebook communities may be hijacked for these purposes. Some colleges are responding by creating their own official FB groups and linking to them from their admission pages. Others are creating their own social networking communities using other tools like Ning.
Brad is coordinating an effort among several schools to figure out what's going on. If you're involved in college admissions, I'd encourage you to read his blog post and get involved.
http://squaredpeg.com/index.php/2008/12/18/facebook-pay-attention/