So who cheated?
I think Linked in is really dependent on what industry you work in. Friends that are tradesmen or non corporate have no requirement for a site like Li. They either have a job where work is provided or get work through word of mouth/trade networks.
I had to create a profile recently & view it very differently from FB as it is a professional networking platform not personal. I am connected with people I loathe but that does not change the fact that we worked together in a professional capacity & you don't have to endorse anyone if you don't want to.
Linked in compliments a professional persons resume & allows recruiters to review a persons claimed skills against if they have been endorsed by others. If someone has "strategic planning" as a skill & has 30 endorsements including vice presidents of big corporations then you can see at a glance if they are the real deal or a bullshit artist.