Come on Axel, Dan said it wasn't an exact science. It also isn't necessary to investigate most accounts. But it is an additional tool. And when accounts are so obviously sockpuppets that a number of members raise concerns, and it turns out those accounts are all using VPN's....well let's just say "what's up with that?".
Sockpuppets are either dupe accounts of a banned member or they are second accounts of a current member, using a make believe "member" to create credibility where he otherwise has none (no one believing him and his claims). Both these are supposed to be against the rules on both forums, so if there is a method another tool, to cut down, it should be applied. That was my point at WoV where we all know the sock puppet thing is running rampant right now.