how is 4ch spam protected?

short question: how do you protect your board from automated bot spamming? i cant see any captcha! normally, from my expirience, a board  would  be instantly spammed to death without captcha or such protective measures. but 4ch board seems to be free of those problems... how do you do that ?

99% of the time, hidden fields, and maybe some really simple and straightforward heuristics are all that you need. (For example: dump any message containing "[url=" or "<a href=", or any message containing the same text in more than one of the fields -- a lot of spambots just fill in the same text in every field, because they generally suffer from amazingly clumsy programming.)

That's really all it takes. I've been running a board for over a year, and have yet to see one single successfully posted spam message since I added these checks. Stupidly obvious or not, spammers haven't bothered to adapt to this technique yet.

For a while, I logged the IP address and post data (just the form field text, no attached files) for every foiled spambot attempt. The logfile would take up more than a megabyte *per day*.

Captchas are a stupid way to prevent spam. They're easier to break than one might expect (have a look at PWNtcha), and they do more to annoy legitimate posters than to curb spam. Simple tactics like adding a hidden field are just as effective and don't get in the way of normal posting. About the only thing they're useful for is slowing down flooders, and a "delete all posts and ban IP" button -- even as short a ban as 15-30 minutes -- is still more effective.