The thing is we will never know if they keep track of our profiles, atleast google is honest about it. It could be that they profile people , but just not openly. The NSA has a very very very very dirty history. Check the book:"The Puzzle Palace".
You can see more on Linux mentor here: https://www.reddit.com/r/linux_mentor/
I did an intro post few months ago when I joined steemit: https://steemit.com/linux/@netscape101/how-to-get-into-linux-or-linux-system-administration
Let me know if you have any questions regarding Linux mentor. :)