[gwern]

But... why is an organization of PhDs solving CAPTCHAs? Even if they are the most expensive service, it still seems to offer terrible hourly returns. That only raises the mystery.

[aristus]

An organization of PhDs writing software that solves captchas.

[roel_v]

"it still seems to offer terrible hourly returns."

Not if they train software to recognize letters. Once they succeed in that, they essentially have a money printing machine for a while.