We have had a little problem of late with spambots..
Unfortunately as any forum software becomes more popular then people will try and find ways of exploiting it... For some time now there have been web bots that have successfully cracked SMF's image verification software and it is a bit of a race between the creators of this software and the makers of SMF.
I've been patching the forum like crazy, some of you may have noticed that we are up to version 1.9 now, and today after three bots got through I decide to add another mod, there is a random question now asked at registration to determine if a user is human before allowing registration, if this mod doesn't work then I'll write my own but in the meantime apologies for these fake accounts, hopefully the problem is fixed now.