Whenever you try to register on a website or comment on some blog page, the site usually asks you to type in a combination of crazy letters and jumbled numbers. It can be a bit frustrating when you cannot make out the different between a ‘L‘ and an ‘I’ or a ‘1’ and an ‘I’. And it can be very nerve wrecking especially when they are all twisted and waved out. Or if you are in a bit of a hurry to get the task done.

This is CAPTCHA.  And it is a human response test. CAPTCHA is an acronym for Completely Automated Public Turing test to tell Computers and Humans Apart. It’s a test to know if the person typing or attempting to do the task is a computer (automated system) or a human.

Why website have CAPTCHA?

Websites have a CAPTCHA code in order to avoid spam. The crazy and jumbled up letters are a way to check if the one who is typing  (or decoding the letters) is a human or a computer that is programmed to spam a site with comments or download stuff or register electronically. Just like you have a spam blocker on your email, website have CAPTCHA codes employed to block spam.

Spam is nothing but junk mail. And if blockers were not installed they would fill the house and yard and everything else on its way. It is a bit irritating and sometimes even frustrating to decode these crazy letters from an images but it for a good cause. And is totally worth it in the long run for the website and your own good too.

Other Applications of CAPTCHA

It is CAPTCHA that helps avoids internet bots (internet robots) from scrapping off important and sensitive data from websites.

– It is CAPTCHA that stops internet robots from taking part in online polls and swaying results by giving huge number of false votes
– It avoid bots from posting numerous commenting on sites or blogs with spam links and flooding sites with junk in general
– It also restricts the robots from registering for uncountable email accounts that are free for people
– It is CAPTCHA that helps protect sites from losing dats like emails information of people to bad bots. That intend to misuse this information to send spam later.
– Or from downloading unlimited photos from sites that give free images, or downloading huge quantities of other multimedia content from websites.

How exactly does CAPTCHA work?


What captcha does is show you a sequence of letters and numbers that are difficult for a robot or electronic device to decipher or decode. These are mostly .gif images of CAPTCHA phrases (with worlds, numbers and letters) along with a .mp3 video recording of the same. These are difficult for regular computer programs to understand. So bots are not able to type the correct response to the image or audio. Thereby telling the system the difference of an electronic spammer from a human.


So next time you have one of these CAPTCHA screens pop-up just smile and decipher the ‘Q’ from the ‘O’ and know it’s for a good reason that it has been employed. And blame it on the spammers because of whom you have to squint and read and type and wait and the move on.