There’s so much choice available that customers can pick and choose who they buy from and where, when, and how it happens. They want to discover, research, evaluate, and purchase on their preferred channel. Give them that option, and they’re more likely to choose you. That’s the whole point behind the multi-channel approach.
If you're only using LinkedIn as a glorified business-card collector, an email replacement or some kind of Facebook counterpart for business contacts, you're missing out on its recruitment potential.