Is it possible to receive data from the profiles of social networks of users who have visited the site?

Question

Social media

This question was asked, as one office writes the following
"getting a complete list of profiles (on social networks) of those people who visited your site (using a special software tool);"
So I thought - what kind of software can it be? On the side of the site, if something is worth it, social networks will not give anything without the consent of the user, right?

Answer 1

There is a subtle way.
Idea: there is a certain service whose code is present on many Internet sites. (counters, pluso social buttons, etc.)
User visits site A, receives a cookie from this service there.
The user visits sites B,C,D,E... - the service already knows that this is the same user.
The user on any of these sites is authorized through the social network - the site transmits the received data to the service.
There are no other ways.

Answer 2

Social networks leave cookies on users' clients, this "special software tool" simply reads all the cookies it knows and extracts information from them that identifies the user. Then everything is simple - the standard social networks API is used.

Answer 3

damapic , thanks for the recommendation!
soon there will be Facebook, Google. We do not stand still, we constantly improve technologies.