Stop Spam. Read Books.

This is one of the most brilliant user messages I have read so far.

Stop Spam. 

Read Books.

This comes from reCaptcha, its the most unconventional way to digitize books. The part about digitizing is the least exciting. How they digitize it, now that is fascinating. Internet in all its glory, passing through the digital lives of several million people a day (its still million, what a shame), helps digitize the written word. 

We have encountered several login pages in our net time. After logging in, we are sometimes welcomed by two weird looking words, and a blinking cursor that wants us to identify them and type them in the text box. What for? To know that we are not programs but humans capable of deciphering those letters. But aren't we all programs in one way or the other? Well, that later.

The prompt helps curb spam and it also helps digitize books. Each of the two words is from some text (books, newspapers, etc) which is being archived in digital text. With every person logging in, and identifying the words, they indirectly help digitize those two words. 

A lot can be achieved by collaboration, but I never thought of this one :)

Good work Captcha...

PS: How does the system know that words being typed are correct or not, if we are the one's to identify them? - 

"Here's how: Each new word that cannot be read correctly by OCR is given to a user in conjunction with another word for which the answer is already known. The user is then asked to read both words. If they solve the one for which the answer is known, the system assumes their answer is correct for the new one. The system then gives the new image to a number of other people to determine, with higher confidence, whether the original answer was correct." 

- from reCaptcha website