dudibob - 12:37 pm on Sep 17, 2009 (gmt 0)

How about what color is the blue sky? Actually, the sky is colorless. Its the refraction and scatternig of the blue light that creates the illusion that the sky is blue. You may test it out at night.

If I ever have to answer a CAPTCHA with an answer like that I'm leaving the internet...

But on topic - I got a feeling this will be more closely related to identifying images rather than Google spying on everyone who completes a CAPTCHA, unless they place ads within CAPTCHA's!