Are CAPTCHAs sending your users away?

[londrum]

I've got a forum-like area on my site, where people can ask questions and sign-up as a member etc. It always used to have a CAPTCHA on it to stop spam sign-ups, and for guests to post, but I recently installed a behind-the-scenes spam prevention script instead and removed it. To my surprise, the number of people signing up, and guests asking questions, shot up. By quite a lot.

It seems that the CAPTCHA was either putting a load of people off, or preventing genuine people from progressing further. And it wasn't a hard one either -- i thought it was actually quite easy (which is one of the reasons i removed it). Any person with more than two brain cells could have filled it in.

So I was just wondering if CAPTCHAs are more trouble than they are worth, given that there are so many other ways to stop spam nowadays.

[rogerd]

Some kind of human verification is useful, but incomprehensible captchas are not the best. I've struggled with them myself, and it's easy to see how an unmotivated user might try once and move on to another site.

I installed a vBulletin plugin that uses a multi-layered defense including Akismet; it didn't stop all spam registrations, but minimized them. The only strategy I turned off was username recognition. So many common usernames have been used by spammers that legitimate users attempting to register with those same names were getting blocked.

[cre8pc]

I hate Captcha's but am forced to used it for the forums where I am an Admin. It's crazy what we go through...captcha, a question, a spam catcher running in the background AND a human must let them pass. And still we get spam posts. The little buggers are persistent, the bots learn and some people think they are above the rules. I agree that a captcha would prevent posting. Once in, there should be a matter of trust there.