[pesfandiar]

In my opinion, the legal aspect is unclear too. In case of brick and mortar stores, AFAIK, most jurisdictions require a noticeable sign revealing surveillance/videotaping. The law hasn't quite caught up online though.

Regardless, I'd say it's ethical if they clearly tell users they're being watched. I bet no one would use the service if it was required.

[jeffreyrogers]

Yeah, I'm not totally against the idea, but I know a lot of people have concerns around privacy online and how data about them is collected. I agree that you should let your users know you're tracking them in this way if you use something like this.