Actually a more complex to manage but could be more effective hack may be possible. A "human decoding farm" Basic concept is the "signature" of a captchas type challenge is routed to a human - who reads and decodes it- types it in and is instantly rewarded by... The next captcha to decode. rinse lather repeat for 8 hours or more a day. But such labor gets cheap . After all when wal-mart self checkouts merchandise made in Bangladesh and stocked by robots we ALL may wind up being captcha decoders for a spam haus.
Don't laugh- some high yield cybercrashings for financially rewarding data can pay .25 each hit At one "hit" per 10 min decoding session your resident of Calcutta earns his $1.50 hourly the hard way.
Oren
ObSciFi-Wolfsbane by Frederik Pohl and C.M Kornbluth. Briefly carries the concept of humans as components a bit farther. DejaVu of the Matrix movies but much better executed.