I harbor a strong distaste for CAPTCHAs. At best, they're annoying. At worst, they're infuriating, such as when I simply can't see the letters or when I stumb

I harbor a strong distaste for CAPTCHAs. At best, they're annoying. At worst, they're infuriating, such as when I simply can't see the letters or when I stumble into a cross-site hosted CAPTCHA that requires JavaScript -- which I have disabled -- and then loses the post I was going to make when I press the back button to try again with JavaScript enabled. I see CAPTCHA as a bandaid and I can understand why people turn to it: spam has reached epidemic proportions. That said, any form of CAPTCHA, either the existing form or the proposed 3-D form of this article suffers from two fundamental flaws: 1. It annoys users and makes it harder for people to contribute 2. Spammers will get around it eventually, and once one spammer gets around it, they all will CAPTCHA bears similarities to copy protection schemes in these two flaws: both annoy users and merely are road bumps to the undesirables (spammers and crackers). I think the solution is three fold: 1. Make it easy to post so real humans contribute 2. Filter spam aggressively 3. Incorporate trust mechanisms Making it easy so real humans contribute removes obstacles (such as CAPTCHAs, registration, etc.) that get in the way of people posting. Every obstacle means less people will post. With community contributors at about 1% of visitors, there's a lot of room to grow by making it easier to contribute. Spam filtering works because spam is fundamentally different from a valid post, and always will be. Bayesian schemes such as pg described long ago work well. Gmail, for example, does an amazing job of filtering spam. The few posts that get through are easily dealt with. Trust mechanisms take advantage of the fundamental weakness spammers have: they aren't members of the community. A simple trust mechanism is don't auto-link links from posters with less than 10 comments. Since most spam contains links of some sort and most comments don't, spam will be predominantly affected by this. Once a posters get to 10 posts (or 10 karma), their comments retroactively get auto-linked. This is simple to implement, but reduces the impact of spammers significantly since their spam isn't accessible unless someone goes to the trouble of copy-pasting it, preventing accidental clicks by users. At the same time it doesn't punish new users, since their valid links will still be accessible and will become on equal footing once they grow into the community.