Looking at my web statistics I see that the most viewed page is ucp.php - 1000 times. Whereas the main page only gets 80 hits. I wonder is this spam bots trying to crack into my forums? I am using phpBB3. The forums are more or less dead, so it doesn't make sense that there are so many hits.
I have a phpBB2 forum - heavily MODded against SPAM bots -
It has been 1,354 days since the last SPAM Robot successfully Registered/Posted to this forum.
In that time, this forum has blocked over 22,724 Registration and 33,203 Posting attempts by SPAM Robots.
So you can see they don't stop trying.
My forum is extremely quiet, so same with me, the majority of requests are bots.