[kh99]

Originally Posted by final kaoss

*Check session for quick responses (disabled if caching is active): Checks that the spammer is allowed to use a PHP session. If not, it denies the comment. The plugin puts a timer in the session and if the user fills the form in less than 6 seconds it is too quick to be human. (Stops the most spammers of all the methods listed here.)

There are several mods that check for the registration form being filled in too quickly. (the one I made is here: https://vborg.vbsupport.ru/showthread.php?t=294633) . It uses a hidden form field (I don't know if I understand the PHP session thing, but maybe it's another way to do the same thing).