Captcha verification code

An image (usually containing a randomly-generated, and oten distorted, combination of letters and numbers), is created each time the page is loaded. The user (you!) has to enter this code into the text box of a form, thus aiding in securing the form against use by automated spam robots.

In practice, some robots are able to read the code these days (October 2006), especially when it is not distorted. However, when combined with other security measures, it is a valuable addition to the Web developers arsenel in the fight against the spread of spam and viruses.