Firstly, there's no session and no client information is stored (like, in a db) server-side, so a huge amount of control most forums take for granted is not possible here. I would have to write the current time into a hidden field, which of course could be faked easily. It would at least be new and unique enough that automated bots would be fooled by it, but considering most forums have flood control, bots are already programmed to wait between posting.

Secondly, I don't want to impact any user's ability to post without unexpected things happening. Bolstering discussion is about removing all barriers, which is why this forum has no CAPTCHA. I didn't want anything to impede users, and forcing them to wait in order to make a reply is annoying and ineffective. I’m fighting spam, not users :)

The fix I’ve made is quite ingenious and involves a magical property of web browsers that few realise is present. I’ve never seen any forum ever use this feature. I won’t describe it, I will leave that up to people browsing the source (this change is not on GitHub yet).