I've been watching them and a large number of the IP addresses are actually owned by Baidu Japan. Since they are a search company I am going to guess that their search spider is lacking in manners.

Nothing too concerning yet! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Tom is right though, the number of attempted spammer sign ups lately has grown to some big numbers!

edit: Just nuked another 5 of them actually..