Since I’m on the topic of LinkedIn I’ll mention this interesting experience.
Someone I was supposed to talk to was introduced to me with an accompanying LinkedIn URL.
https://www.linkedin.com/pub/theguysname/5/428/205
Since I didn’t understand what the trailing numbers were I assumed the worst, that they were to track me. Instead of using that supplied URL, I searched for the guy’s name in the LinkedIn search box. I did this while not logged into my account. Strangely LinkedIn showed my picture, and assumed I was the user (probably based on IP number and/or cookies). The problem is that if I was not the user, say I had borrowed someone’s computer, it would be highly misleading to see my photo with the caption "Chris X Edwards - Research at Sandia National Laboratories" which LinkedIn showed. I presume it was a job ad, but to someone who is not me, it looks like I not only would condone working for a source of nuclear weapons but that I currently actually do!
I found the guy easily enough and was able to see his full employment history. LinkedIn then told me that to see his full profile I need to log in. Fine, be that way. After I logged in, however, I could no longer see his employment history. Or anything! They even suppressed his last name which I originally searched for!
With LinkedIn, it’s definitely a fine line between being a user and, as RMS calls them, being a "used".