I have a number of sites that allows users to post nodes and comments, however bots are getting a hold of these and having their way with my site. I recall seeing a module a while back (but cannot remember it's name) that allows admins to set a time limit between posts. Basically denying posts that made within minutes or seconds of eachother. Any ideas?
Maybe Node limit module can help? I haven't used it but it seems that this may be what you need.
Honeypot seems to be your solution. I discovered it after i used mollom but it seems very useful.
Honeypot uses both the honeypot and timestamp methods of deterring spam bots from completing forms on your Drupal site (read more here). These methods are effective against many spam bots, and are not as intrusive as CAPTCHAs or other methods which punish the user