There are two main schools of thought with LinkedIn: Using it as a resource tool, or being the resource. You should really decide which one you are and stick to it.
Excerpt from Gonzo Sourcing and the Evolution of Online Social Networks
The following is an excerpt from "Gonzo Sourcing and the Evolution of Online Social Networks" By Shally Steckerl. Read the entire article here. Shally is a guru when it comes to candidate sourcing and recruiting, and his whole article speaks to this more in depth, but the section I'm clipping is specifically applicable as well to the job-seeker.