How to stop spammers in ASP.NET?

I’ve found a great way to stop spam in ASP.NET. There’s a free captcha control for asp.net (click).

A captcha is just a fancy word for one of those neat images containing letters or numbers that you’re asked to copy into a text box before submitting a form.

People can read them. Computers can’t. It’s that simple.

This one support a mixture of stuff. You can add wavy lines to the background, stipulate the length of the code and pick a mild, medium or severe warp for the letters. The generated code is stored to the session. It works, it’s fast and it does the trick, and best of all, it’s FREE.