An e-mail adress can be had for free an totally anonymous at various hostings. Hell, you could just log into Hotmail and create an account under a weird name within 2 minutes. Try and trace that !
Than if one is careful enough to use a provider with DHCP IP adress assigning then not even that can be used to pinpoint a given user. Only his broad location. Sort of like the user is somebody in North Carolina. Not sufficient to stand up in court, I say.
One can just as well map lunar brightness to geographical location and get the same broad result. HOWWWWLLLLL !!!

(F16 insider joke)
Wouter