I administrate a few PHPBB3 forums, and recently noticed one had a BIG spam problem. I had naively assumed that PHPBB3′s version of CAPTCHA would stop the bots at the gate – oops.
Manually deleting 100′s of spam accounts from my forum wasn’t fun.
Determined to prevent this from happening again, I asked Google what to do. Google’s answer was this:
It’s effective, integrates well and is easy to install.
You don’t want to experience a bot infestation – prevention is better than a cure.