Rojas-Lozano claimed that the second part of Google’s two-part CAPTCHA feature, which requires users to transcribe and type into a box a distorted image of words, letters or numbers before entering its site, is also used to transcribe words that a computer cannot read to assist with Google’s book digitization service. By not disclosing that, she argued, Google was getting free labor from its users.

I refuse to work for Google and specially not if I am not getting a salary !!!

challenges/unpaid work assignments for Google