It's a Bottom-Feeding Parasite's Wet Dream!
My overriding experience of LinkedIn is one of bottom-feeding, parasitic recruitment agents, merely wanting access to your network so they can continue to bottom-feed.
Tell me, is there some kind of quota imposed by the recruitment industry that agents must try and hit?
I can honestly say I've never had a job opportunity come from a recruitment agent on LinkedIn. Company CTOs, MDs etc. yes. Agents? Not a bean.
Same with applying for roles on the job boards (JobServe et al.) I can't think of a single instance in the last five years where I got an actual reply for a role I've applied for through them. Then again, now I think about it, there's probably not much cross-over and demand for software engineers in the Picking Peanuts out of Poop industry!
A cynical individual might start to think that most of the posted roles on the boards are just fishing for CVs to fill that all important quota.
There was a time when people could obtain gainful employment without the need of these parasites!