PHP Programming Spam Prevention

Question

What is the most secure way to fight spam?Any algorithm?Or way to fight back spammers?

Answer 1

Get a captcha dude, it's probably the best way to defeat spam. Here is a great one called reCaptcha. It's pretty easy to integrate with PHP and is mighty effective. Here is how you do it.

Answer 2

DNSBL's? There is an API available at www.atlbl.com that you can query to check for botnet's/spammers/etc etc

Answer 3

Akismet is outstanding at catching form spam.