Recall actually is a brilliant idea, and I dreamed of something like it for a long time, and so did plenty people here. It's just not something you can trust a third-party business with, whether it's a fly-by-night startup or an international megacorporation known to be openly promiscuous with advertisers.

This is basically "take a screenshot every 30 seconds and compile it into a timelapse", but on steroids, and the same appeal, and arguments wrt. who gets to run it on whose machines, all apply.