DVR
Definition:
Here's a word you may not know...
reCAPTCHA
reCAPTCHA is a variation on CAPTCHA in that rather than displaying random letters and numbers, reCAPTCHA actually displays real words from old texts that have been digitally scanned. The words displayed were not understood by the computers that scanned them. Thus, not only are you preventing spam by entering the reCAPTCHA words, you are actually helping to decipher the words and bringing the old texts into the digital world.
For more information on reCAPTCHA, visit www.recaptcha.net.