How to go about trying to figure out someone's identity online?

[clickynext]

Someone's been posting insults on my friend's blog lately, and we're more curious to find out who it is than bothered by it. The insults are really meaningless, but they are personal so we know it's someone whom we know. The blog is on Xanga. The account they use to post the comments is completely devoid of anything. Looks like they were so bored that they created accounts just for the purpose.

Any ideas?

 

[FoBoT]

does this blog thing allow you to log the IP address of posters? or do you have access to the logs of the website?
once you get the IP address, there are sites that will map it to a physical location
also, if it gets out of hand, you can contact the ISP and get more info about the person, maybe or at least get them in trouble, maybe