I once had a discussion with a chairman of a major group about how he chooses CEOs for his companies and he replied: all things being equal, I pick the ones who read most. This guy hires CEOs who in turn higher thousands of people. Although reading consumes a portion of your time
As a recruiter I hardly recall an incident in which we hired a fresh graduate because we liked his or her resume we saw on LinkedIn. The same applies to other recruitment agencies as they use LinkedIn to identify candidates other than fresh graduates. LinkedIn is only used by recruiters to find people with experience.