This is the place to discuss ways to prevent robots - register, post and etc, in the forums/blogs/etc.

The well known methods:
- CAPTCHA
CAPTCHA - Wikipedia, the free encyclopedia
- Email Verification
- Huge Database to keep track of spammers
- Waiting for Human Approval
- Answering some questions
etc

Examples for the discussion:
Will it help if hardening/making CAPTCHA complex?