My site is being really hammerred by comment spammers today but not one has got through thanks to my policy of refusing to allow comments containing urls to be submitted (not even for moderation: I moderate all comments, I found deleting comment spam to be tedious as well as annoying).
It is a simple hack to the drupal comment module but it is very effective. Ok, I could get spam without url's in but what's the point, apart from vandalism? They still go into the moderation queue and get deleted.
And when people do want to post url's they soon figure out how to get around the block. If they cannot do that then their comments are probably not worth consideration anyway.
I'd give the details of the hack here but it gives the spammers a clue. If you are interested then email me.
Update: following on from the vast surge in comment spam attempts (three or four a minute, 24/7), statcounter tells me people are searching for drupal captchas. I have given up on these, something about drupal states, redirects, session management or whatever stops them working reliably. The spam comment check is just part of the comment validation, there is nothing much that can go wrong with it, it is just straight if/then/else code.
In a way the spam check is a captcha (Completely Automated Public Turing Test to Tell Computers and Humans Apart), you can still get through if you show some smarts. It doesn't use graphics so it doesn't look cool and it doesn't shut out blind people.
The comment spam is coming from a range of ip addresses, maybe an array of compromised pc's (thanks Microsoft). Each 'failure' page is using some of my 10G/month bandwidth. I'll have to keep an eye out and see what kind of impact this is having. It could be even worse than inktomi slurps bots doing 100M of crawling a month and not directing anyone here through their search results.
Twitterings
Peter's Moblog
Yes!
Its so bloody annoying! By the way your page rates pretty high up on drupal comment spam search!
I'm ginving the "spam" module a try to see if it averts some of this spam that is coming through lately.