Collaboration between google map and reCAPTCHA
I think the collaboration is useful and works well. The original article is here. This is interesting for me.
Google Online Security Blog: Street View and reCAPTCHA technology just got smarter
The normal CAPTCHA is a web technology which you can often see when you login to some websites. It is often some distorted characters with some lines or dots which is possible for human to read but for computers. This is usually used for prevent 'bot' program from attempting sign up web services mechanically to create bunch of IDs or something else.
On the other hand, AFAIK, reCAPTCHA is almost the same as the CAPTCHA but it provides 2 words, the one was already known by the server and the other wasn't known - it's too complicated to be identified by machines.
Once a user types these two words in a login form, the server uses the one which is already known to identify whether the user is human or bot, and stores the other to it's database. The word will be shown to several users and the data input by them will also be stored in the database. Eventually servers can identify the unknown word from collected data.
These words analysis seems to be used for google map. And it is used for digitizing existing books according to this.
I like this kind of "killing two birds with one stone".
