Well actually it is more like they you are entering their store. They are measuring the number of people that come in. The number of items (and what items) thes

Well actually it is more like they you are entering their store. They are measuring the number of people that come in. The number of items (and what items) these people look at. Add to their basket. How many stand in line at the cashier and how many buy. And how many filled baskets stand in the isles at the end of the day. But - they also could write down the gender of anyone entering the shop. Or the hair color. Or they could note down the license plate of your car. With whom you arrive. The brand of your car. The color. The brands of the clothes you visibly wear. Then they correlate that to the payment method, your Visa card, the credit ranking they receive back from visa (digitally at least). And so on. and they measure how often you return. They could do all of this (and actually a big lot of them does) and not only log that for themselves and do whatever analysis with it, but also send this data happily to the advertising agency that manages the big signs all over town so that they can show you additional advertisements for a new car, because you have money, but your car is old. That is were the problem begins. It begins when doing way too invasive logging of user attributes that do only marginally have anything to do with measuring how the shop (or the website) work. And more so when this data is being sent to who knows whom in this advertising space out there. I have no problem with an online store storing the fact that I came by clicking on a display ad. Or on an email newsletter. Or that I am using Firefox. Or Chrome. And that I am on a WIn10 desktop device. Or that I tend to add a lot of stuff to my shopping cart, wait two hours and then sort what I don't need. I even do not have a problem showing me additional products based on what I looked at in their shop. But to correlate that with offsite data, sending this to advertisers and so on is a no go for me.