I don't mind LinkedIn, it keeps my professional life distinct from other social media. Yes, some of the posts are toe-curling, but mostly it's a resource for finding people. Professional stalking I call it. It also satisfies those idle 'I wonder what they're doing now' queries about former colleagues and associates (and exes).
Yeah, I get a lot of recruiters contacting me to sell me candidates, but you can (and I do) ignore them. I get a lot of people offering me jobs (or at the least the opportunity to apply for them, some on target, some off). The quality of CVs we get via LinkedIn are variable, it does get a backwash of keyword-based applications, but I work in a field where direct recruitment is a far better option, so LinkedIn is a good resource for finding who's who, and who works in similar teams for our competitors, so we can sic the 'talent acquisition' (HR is always going to HR) on them.