ReCaptchas are generated by failed attempts with OCR, which means the computer has no idea what the word actually is, and consequently can't know how it should be oriented. ReCaptachas are actually digitizing unknown text, so they serve a pretty meaningful purpose in contrast to competitors. http://www.google.com/recaptcha/learnmore
recapcha started for a noble cause and thats why it got so much traction.
Instead of fighting bot menace, current captcha's are making life difficult, if with my intelligence I end up failing 1 in 10 times, how can my dad or my 7 year old daughter use it.