I wonder if they deliberately put a line through the "real" one (the one from a book) to make it look more "captcha-like".I think captchas fall down in this way:Some spammers need a lot of captchas solved cheaply.They set up a porn website.Before you can download an image/video you have to enter a captcha (allegedly to stop people data-mining their site)The captcha is actually copied from a web site that they want to authenticate themselves to (for spamming purposes)The person wanting the porn solves the captcha for them. They get their porn as a reward.The site use the solved captcha to spam someoneI really LOLed at this one. In fact the "double captcha" works well here. They would use one generated by themselves to make sure that people don't get porn for nothing (which would mean they don't have to work too hard at the captcha). The other one is the one they really want solved.
After watching the CAPCHA video, I was left with one major question.. How does the computer know that the capcha that your translating from a book is translated correctly? I guess next time I read a book online and see a word that clearly doesn't fit I can blame some dyslexic kid trying to sign up for yahoo! XD