Old fart here.
I can sort of see the point of Facebook although I don't use it to post anything. I still use telephones and that newfangled email thingamabob to contact friends and family... I accept that Facebook may be used to get money from ads, and although I don't know how that works (don't see many people admitting to clicking on ads) the sheer volume of people and posts may make it viable.
But I honestly can't understand what Microsoft gains from LinkedIn. My brief foray into LinkedIn ended after few months of many, many messages about people I may know but I didn't want to contact anyway, and requests for acknowledgment from people I never met. It looks like a nice way to keep professional information and contacts, but there is too much noise, and it comes from LinkedIn itself. Same thing (or worse?) with ResearchGate, who decided I wanted to know all about all people that may or not be friends of neighbors of teachers of cousins of coauthors of papers I briefly showed some interest on.
Can one of your young whippersnappers explain how will Microsoft monetize it and then get off my lawn?