On Fri, Nov 18, 2011 at 1:56 PM, Tony tony@ttiger.co.uk wrote:
I run a forum and the number of spam signups was getting beyond the joke. I used to do as you have been doing and block the IP's but they always popped up again. The majority are from bots and most now can crack a Captcha. What has proved to be most effective is having a simple questions and answer, I just have four that randomly rotate on each sign up. Haven't had a single spam sign up since I done it. http://www.xaprb.com/blog/2006/01/28/captchas-done-better/ gives an idea for PHP coding.
Have you noticed any drop off in the number of new user sign ups since you implemented the questions? It's surprising how many people can fail to answer even the most seemingly simple questions correctly.