Ask HN: Captcha Alternatives?
* Allow new accounts, but hide messages from them until their posts are verified manually and the accounts are either approved or shadow-banned.<p>* Don't delete ban accounts, don't notify them in any way, but tag their IPs and cookies to auto shadow-ban any sock puppets, so that these don't even make into an approval queue.<p>* Use heuristics to automate the approval process, e.g. if they looked around prior to registering, or if they took time to fill in the form, etc.<p>* Add a content filter for messages, including heuristics for an ASCII art as a first post, for example, and shadow-ban based on that.<p>* Hook it up to StopForumSpam to auto shadow-ban known spammers by email address / IP.<p>* Optionally, check for people coming from Tor and VPN IP, and act on that.<p>Basically, make it so that if they spam once, they will need both to change the IP <i>and</i> to clear the cookies to NOT be auto shadow-banned. You'd be surprised how effective this trivial tactic is.<p>All in all, the point is not to block trolls and tell them about it, but to block them quietly - to discourage and to frustrate.