Just in case you don't know... when someone refers to Captcha, they are talking about those numbers and letters you are required to enter into some websites before you can register or login. The official definition is :
CAPTCHA is a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot. For example, humans can read distorted text as the one shown below, but current computer programs can't:
You may not like them, but they can help reduce the number of spammers registering at some site. The reason you don't like them is because some of them...like Micorosft's and Googles are just bad implementaion of a good idea. You can't read theres, and just for grins and giggle...click the icon to play them sometime. If you can understand it...then pat yourself on the back.
Anyway, we have installed and implement Capthca on the NHS website to help keep the bad registrations down.