On: How to Force Facebook into Handing Over their Secret Tracking Data

[nl]

I doubt they HTTP access logs are tied directly to the user id.

It might be possible to derive this information by linking on the IP address, but that isn't the same thing as a direct link at all.

[_delirium → nl]

Facebook is able to tell which profiles you view more frequently than others, so some sort of log data correlated with users is being kept.

[nl → _delirium]

That's different to HTTP access logs.

If I view a profile on the mobile app or on the web page it is (presumably) measured the same, presumably in the application layer. That's different to recording the your id in the HTTP access logs.