Protect Against Form Bots / Spam Bots

[eluser]phpmonster[/eluser]
Haven't had spam from spam bots since ever - last night I get like 4 dozen on my CI sign-up forms which use the regular form validation and processing.

Do I really need to start using Captcha service with CI? Anyone any good ideas to prevent spam bots from submitting bogus form info?

[eluser]Bart v B[/eluser]
Well.. what i did is create a hidden form field with a simple but common name like 'e-mail'.
And when the value is filled, then do nothing or redirect to some strange website...
It's not waterproof, but an option.

[eluser]LuckyFella73[/eluser]
A simular option is to set up a hidden field containing
a default value. Change that value with javascript (after
document is loaded) to an other value and then check
in your controller if the value is equal to the value js should set.

I read that spam bots usually don't support javascript so
the value would be the default one (or an other, in case the bot
changes the value) when submitting.