Captcha

Captcha are images that are used to deter automated registration and is a way to check to see if it is a person or a program submitting the comment/registration.

It is not really necessary to perform the programming yourself since there are a lot of free tools/components that you can use.

Some of my favorites are:

1. CodeProject
2. Free Captcha - but not sure how it will impact the performance since it needs to talk to the provider.

One thing to be aware is how the captcha images appear. The following website shows some of those to avoid.

Other things to be aware of captcha are:

1. There are now more sophisticated tools to defeat the captchas.
   
2. More and more users are getting upset and turn off by captchas so it may cause you to lose your main customers.