LinkedIn just to see what companies are working on or doing, what jobs are out there, etc. I don't really follow people/posts, just do my own searches.

LinkedIn is something you keep only to be seen by recruiters.

I don't really interact with anything there, but I keep an up-to-date profile and sometimes post some technical articles or tutorials. I put the some effort on those, but I don't care if anyone reads it. The purpose there is just to have some well-written technical articles under my name.