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In my experience simple, domain-specific CAPTCHAs work pretty well. They don't even need to include a frustrating image with hard-to-parse words. Just ask comme
by Udo 15y ago
In my experience simple, domain-specific CAPTCHAs work pretty well. They don't even need to include a frustrating image with hard-to-parse words. Just ask commenters a somewhat randomized question that any visitor to the site would be able to answer easily. It can be really, really simple - like for example asking them to enter the abbreviation for something:
> Whats the abbreviation commonly used for the Hypertext Transfer Protocol?
This weeds out bots (because they generally don't bother with site-specific stuff) and many trolls (because they are either to stupid or to lazy to go through this process).
- joelthelion 15y agoThat would work well provided your site isn't a high traffic site.
- Udo 15y agoYes. The lower traffic your site is, the easier you can make the captcha. The truth is, most of us have pretty low traffic sites with no more than 100k hits per month, blogs for example. The key here is to have a simple but different captcha compared to the standard stuff. Pairing this strategy with a little bit of site-specific domain knowledge goes a long way towards discouraging trolls and idiots. I think overall, bots would be negatively impacted by a more diverse captcha ecosystem even if the individual implementations are easier to crack. Spammers don't invest 10 or 20 minutes in cracking a domain-specific captcha system just so they can spam one single blog - they'd rather move on to thousands of sites that are protected by the same standard word reading puzzle. Of course, if your site rises into the upper strata of the web, you're also quickly entering a zone where the standard, hard-to-decipher image strategy isn't working so great anymore either.
- rocktronica 15y agoAnd that the question randomizes pretty well. Otherwise posts could be automated.
- CWIZO 15y agoJeff from coding horror for a long time used a very very simple "CAPTCHA". You just had to enter 42 (if I recall correctly), and it was always just that, nothing random. It served him well, and he has a high traffic site (http://www.codinghorror.com/blog/2006/10/captcha-effectiveness.html http://www.codinghorror.com/blog/2006/10/captcha-effectivene...)
- dredmorbius 15y agoThe other use-case is defeating chaptcha-solving farms often run out of locations with low labor costs. I'm not entirely sure a specific cultural / intellectual / domain knowledge question would be more effective than simple character recognition, but it might be an interesting test.