[ffriend]

But isn't A/B testing doing the same thing? If it's different, what's the key difference between analyzing facial expression in a shop and analyzing user interaction on a site (given that both have a warning about data collection)?

[arximboldi]

The former has very weak (if any) consent, is indiscriminate, easy to abuse, and creates unnecessary conflict (e.g. i really like those pants sold in that shop but I don't like to be tracked, ok i'll go in just this time...).

In A/B testing there is a clear context and purpose, and is normally negotiated between actual humans.

There might be middle grounds (A/B testing can be done online and use facial recognition and in relatively large scale) but for me it has to be opt-in (as in, you have to fill a form to join) not opt-out (as in, leave this webpage/shop if you don't want my tracking). This is more challenging to the organization proposing the tracking, because they need to provide some value in exchange so people actually sign up for that. But in the long term being founded on the principle of consensual mutually benefiting relationships can only be good for your organization/brand, right? As in: at last a company that treats people like humans!