A study by security vendor Imperva is very depressing, showing the broad collection of programs and people that are trying to systematically defeat CAPTCHA security apps and harvest personal information from various websites.
CAPTCHAS are those squiggly collection of letters you have to type in to prove you are human and not a bot. The only trouble is that they have been routinely compromised. Look at this chart which shows the results from Captcha Sniper which can solve routines from 50 different vendors with success rates that are at least better than 50%.
The report does offer up some hope, however. Along with my story published in ReadWriteWeb earlier this summer, there are a number of innovations in the CAPTCHA space, including game-based algorithms, animations, and combining visual with audio content to create a puzzle that humans can solve with ease but that will be more of an issue for a computer program. Imperva recommends that CAPTCHAs be supplemented with other routines, and security professionals should examine Web headers and do deeper analysis of their content to catch these miscreants.