it could be people reading up on the threads, before deciding to sign up.

it could be people who are signed up, but in sted of using their acounts, viewing the forum as a guest (as they are too scared to post themselves, and use the guest feature because of it)

it could be people who want to use their information for their own purposes (to post other places etc)

it could be absolutely anyone..... it could be some child sitting somewhere not really taking what we say seriously