I wonder how legal coinhive usage is, since it's a great idea, but users for sure will piss their pants if they find out youre literally driveby mining bitcoins. Also how comparable is it to ads etc.

It's legal. Nobody will sue them for that.

The concept is not that bad. They can earn money while not ruining user experience with a shit load of ads.

The only downside is that javascript doesn't have access to cpu usage of client so it can throttle it accordingly, and if you are visiting a such website while running some intensive apps in background, it might be a terrible experience.

@JonnyCodewalker Exactly why I got so interested