This is a situation where something being free or cheap creates negative value. I get contacted through my LinkedIn account every once and a while because someone was looking for a bilingual programmer and we're rare as hen's teeth in my language pair and region. I have never actually been in the market for a new job, but they're typically pitching jobs which would be fairly attractive to me if I was.
I don't get spammed daily by someone who searched for "All programmers listing Java experience" because LinkedIn's business model forces people to a) be serious about hiring from it (or you wouldn't be spending a few hundred dollars) and b) be selective about who you contact (rather than casting a dragnet).
