Not only do captchas fight spam, they irritate people, make them mad, account for 60% of computer failure from being thrown across the room, and stick like a chainsaw in the side of spam bot owners everywhere.
This week, I decided to disable it for a few days on EC. I needed to boost the member count a bit, and wanted to see what happened.
Well, turns out the IPS spam service is quite awesome. I had about 120 spam bot registrations this week and only about 3 or 5 got past that. It was amazing. Not only that, but I recently got a review for EC at Forum Promotion and they were praising my "active" staff - when it was the spam service doing most of the work. lol.
However, there were a few that were slipping past during the night, so I decided to re-enable the captcha this morning, since we've got over 500 members now.
Anyway, that was fun.