I've never really had a problem with reCAPTCHA, I think it's one of the best out there (I hate websites with home-made text captchas that are crazy impossible to read).
Also, there's a nice "refresh" button right next to it if you find it too hard to read.
i thought one of the best startups i came across last year was Solve Media. that's an enormous problem you're referencing, and not only did their startup solve the problem, but they also created value for brands by advertising within the password boxes<p>check out the venturebeat writeup from last year:
<a href="http://venturebeat.com/2010/09/20/the-latest-ad-frontier-solve-media-lets-you-advertise-on-authentication-tests/" rel="nofollow">http://venturebeat.com/2010/09/20/the-latest-ad-frontier-sol...</a><p>they also put together a great youtube overview: <a href="http://www.youtube.com/watch?v=f-dZvZasg0o" rel="nofollow">http://www.youtube.com/watch?v=f-dZvZasg0o</a><p>it's one of those ideas you come across every so often that just makes too much sense. i'd bet they'll have their fair share of competitors soon enough.
Part of the point of reCAPTCHA is to crowdsource the digitisation of printed content that conventional OCR couldn't manage.<p>This is why you occasionally end up with strange things like fractions and foreign characters, that you don't know how to input.<p>Use the refresh if you can't read it.
I may be mistaken, but I've found reCAPTCHA to be often forgiving, sometimes the words are just not clear, and I just type what I think it is. I don't remember ever being incorrect on the reCAPTCHA.
I also would say it is the best one out there. It is easily readable most often for me, and the 'generate new captcha' button responds instantaneously anyway.