I already responded to your shop analogy in another comment, so I won't do that here. But - > Or is your objection just to the Javascript? If I "violate their

I already responded to your shop analogy in another comment, so I won't do that here. But - > Or is your objection just to the Javascript? If I "violate their privacy" by analysing server logs it's OK, but adding javascript to measure behaviour is "bad, hmmkay"? If you misuse any data you collect from anywhere, you're being a jerk. We're talking about collecting data in the first place. If you collect data by having a webpage visitor execute code on their own computer in the background and send data back to you, they clearly aren't meaning to send you that data, so you shouldn't do it. > Startup 101 "Mom Test" stuff. If you ask people what they think, you get their intentions. If you measure their behaviour, you get actual data. Talking to customers is excellent, but measuring what they actually do verifies that they're not lying to you because they're nice people. Startup 101 is anathema to treating people well. That some data about people could help you run your business better doesn't mean you're entitled to that data.