What is CAPTCHA? It stands for Completely Automated Public Turing test to tell Computers and Humans Apart. It is a test that assists a computer in telling the difference between humans and machines, that has been trademarked by Carnegie Mellon University. With CAPTCHA a computer can detect whether a machine or a person completed a test, and discard any computer answers.

It gives you a test to decipher distorted numbers and letters, which are pretty easy for a person to do, but cannot be figured out by a machine. For further details about CAPTCHA and smart CAPTCHA go to http://www.protectwebform.com/ and http://www.protectwebform.com/smartcaptcha.

Having a CAPTCHA installed can protect against bots, which are programs that can repeatedly spam inboxes, try to post and retrieve personal information in chatrooms, and also try to get e-mail addresses and other information to use for promotions to sell services or items, or sign you up for numerous free mail services.

In addition these bots can put a worm on your system, getting your passwords, and other personal information and taking it back to the Internet for others to use commercially without you even knowing how they got it.

CAPTCHAS and CAPTCHA plug-ins (http://www.protectwebform.com/plugin_wordpress) intend to prevent these bots from creating havoc. The CAPTCHA programs need the user to recognise and then key in a string of distorted letters and numbers in a box. The string will appear as a distorted image over a ?noisy? background. CAPTCHAs are used by various large and small sites. You will find them in mail services, banking sites, blogs, chat rooms and similar places.

Spam seems to unfortunately be way of life. Day in and day out spammers are sending message after message into your e-mail system. But it's not just in e-mail that you may be hit with spam. Spam also is a problem in online newsgroups, logs, search engines and even instant messaging!

The reason why advertisers resort to spamming is because it does not cost much. They have to bear only the cost of managing the list of individuals that are targeted to receive the mails. Moreover, you cannot hold the sender accountable for the mass mailers they send. Spamming has become really ubiquitous since there are no entry barriers. No wonder your inbox is always flooded with mass mailers.

On newsgroups, the spam is Usenet Spam. You may have seen this when you log into a newsgroup you enjoy. You may be trying to read a topic but see that is has been inundated with post after post of some sort of advertisement that doesn't belong there. That's Usenet spam.

The other kind of spam, which is the email spam usually targets individuals with direct messages. The list of ids that are targeted to spam can be created by scanning postings from Usenet or pilfering with the Internet mailing list. This kind of spamming does incur a little more money.