A captcha is a test to make sure you are human. It’s the little picture at the bottom of registration forms, with squiggly lines and blurred letters. It works because there are still a few tasks only humans can solve, like figuring how many cats are in this picture:



Captchas are what prevents spammers from having email accounts to spam you some more. Captchas are your friend, although they could be somewhat annoying when you actually have to solve one:



This is why spammers are paying people to solve captchas, which makes spam less than free. Making it difficult to spam, is good for us.  They pay a few cents for each captcha solved, and this puts a cap on the profit they can get. And  in some regions of the world, a few cents can get you a long way. Captchas help develop the economy.

Heck, Amazon has an entire business built around this idea. The Amazon Mechanical Turk. The original Mechanical Turk was a clever hoax. It was a machine built in 1770 that supposedly knew how to play chess. In fact, there was a midget chess master hiding inside the machine.



Amazon’s Mechanical Turk is a way to connect businesses with people that are willing to do small and simple tasks requiring real human intelligence. And Amazon aren’t the only ones who see the business potential in millions of wasted human brain cycles. Google have an image labeling game that helps them tag images on the web. If you wish to understand more about harnessing millions of human brains for your business, you may want to watch the following lecture (which is totally worth your time, by the way):


reCaptcha is a captcha system that fights spam and helps digitize books:

To archive human knowledge and to make information more accessible to the world, multiple projects are currently digitizing physical books that were written before the computer age. The book pages are being photographically scanned, and then transformed into text using “Optical Character Recognition” (OCR). The transformation into text is useful because scanning a book produces images, which are difficult to store on small devices, expensive to download, and cannot be searched. The problem is that OCR is not perfect.

reCaptcha solves OCR mistakes by showing you two words in each captcha. One word is a known word, and is the test word. The other is a word that the OCR has failed to understand. When you answer the reCaptcha, you verify that you are a human being (kudos!) AND you help preserving the worlds knowledge in digital form.

Why am I using reCapthca?

I use reCaptcha because I hate talking to spambots and I love having conversations with human beings. I want your comment to be worth more than the two seconds it takes to pass the test. This way we can have a meaningful relationship.

Oh, and you can always register with OpenId. That’s good enough for me.

  • Well, it seems spambots are better than thou. I’ve got a spam comment already. At least they have to have a valid gmail account in order to create this message.

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  • Since reCaptcha displyas two random words next to each other, sometimes it creates hysterically insulting combinations. Like this one

  • And I love it all the more for this.

  • And it causes people to spend minutes in failed attempts to fill in longer captchas and driving me (err. them) insane.

    Can’t we just use facebook-connect / open-id or any other technology that will verify once that I am indeed a person and not require me to do so again every 5 minutes ?

  • Sure you can. This blog supports it, anyway.

  • Soon (few months/years) when 85-90% of the users will be part of facebook you could ‘just’ use their ‘connect’ feature.
    That will save us the hard task of reading some unbelievable letters.