Comment by jandrese

> That being said, one point is very correct here - by far the best effort to resist broad crawlers is a _custom_ anti-bot that could be as simple as "click your mouse 3 times" because handling something custom is very difficult in broad scale.

Isn't this what Microsoft is trying to do with their sliding puzzle piece and choose the closest match type systems?

Also, if you come in on a mobile browser it could ask you to lay your phone flat and then shake it up and down for a second or something similar that would be a challenge for a datacenter bot pretending to be a phone.