Terrorism: imaginative detection or illusory means?

Apparently, the IARA in the US reviews Second Life for potential terrorists. The information seems weird, for how can they know who is behind a character in Second Life; second, what about the other offences committed on Second Life, like blackmail, fraud, drug dealing, probably by now money laundering? "Government Continues To Search Virtual Worlds For Terrorists" (26 February 2008)http://news.zdnet.co.uk/security/0,1000000189,39352920,00.htm