When the bots attack! [closed]

Answer 1

Ned Batchelder wrote up a technique that combines hashes with honeypots for some wickedly effective bot-prevention. No captchas, just code.

It's up at Stopping spambots with hashes and honeypots:

Rather than stopping bots by having people identify themselves, we can stop the bots by making it difficult for them to make a successful post, or by having them inadvertently identify themselves as bots. This removes the burden from people, and leaves the comment form free of visible anti-spam measures.

This technique is how I prevent spambots on this site. It works. The method described here doesn't look at the content at all. It can be augmented with content-based prevention such as Akismet, but I find it works very well all by itself.

Answer 2

just verify the email address and let google/yahoo etc worry about it

Answer 3

Animated captchas' - scrolling text - still easy to recognize by humans but if you make sure that none of the frames offer something complete to recognize.

multiple choice question - All it takes is a ______ and a smile. idea here is that the user will have to choose/understand.

session variable - checking that a variable you put into a session is part of the request. will foil the dumb bots that simply generate requests but probably not the bots that are modeled like a browser.

math question - 2 + 5 = - this again is to ask a question that is easy to solve but prevents the bots ability to generate a response.

image grid - you create grid of images - select 1 or 2 of a particular type such as 3x3 grid picture of animals and you have to pick out all the birds on the grid.

Hope this gives you some ideas for your new solution.