All information you've explicitly disclosed to them yourself.

If you'd complained about how much stuff companies like this infer about you then you'd have more of a case about privacy. e.g I've never given Facebook my phone number but I'm almost certain that FB already knows what it is since my friends have it in their address books. Address books which they've (perhaps unwittingly) handed over to countless companies. Even then, me leaving such services doesn't stop them from knowing things about me.

Prior to using LinkedIn I, like many others, kept my resume on a publicly accessible website. For me this means there is zero downside to moving all that information to LinkedIn, and only upsides - While I haven't accepted any jobs that came my way via LinkedIn, I've learned about some interesting new companies I never would have been exposed to otherwise, and I now get some more useful metrics on who viewed my resume.