Web tracking systems. What exist?

Question

Monitoring

Good afternoon!
Out of the corner of my ear I heard from colleagues that in the analysis in the field of Internet advertising, methods are used that allow users to "lead" users from the first visit to the site to the next, passing for analysis the data of all the sites visited by them in the interval.
It became very interesting - I found out that such systems are called web tracking, but I could not find implementations. It seems like google analytics provides something similar with the help of its userID, which can be activated, but I still didn’t understand whether it was or not.
Tell me, are there such systems? I would like to use it only for research purposes to improve the advertising performance of the site.

Answer 1

Most likely, we are talking about all these guys here:
mixpanel
intercom.io
carrotquest
woopra
There you can simply see his history for each user, with the proper settings.
>passing for analysis the data of all the sites he visited in the interval
A, no one will ever give you this :)

Answer 2

Which site the user has visited can be known either by the site owner (by logs and analytical tools) or by the browser (including its plug-ins and extensions).
UserID in UA is used to track the user from different devices (cookies are different).