I am been fighting a serious issue with a underdeveloped site that the bots took control of without me noticing.... One of the ways I have been fighting this has been to log registration attempts.
Attached is the registration log for about 7-days on one of my sites... Note, each one of these registration failues would have been one to many spam posts! Note that the time posted in this is the registration times! Also note I am using the NoSpam question hack as well as several other hacks as well. Also, my list of banned e-mail and IP addresses is huge but they still keep comming!
I have a thread with what I am trying to look at the following link to see if there are other ways we can make the spammers life much more difficult!
https://vborg.vbsupport.ru/showthread.php?t=158544