I've been on LinkedIn for a couple of years now, and one of the best features I use is the "testimonials" feature. LinkedIn creates an easy way to get and show testimonials, something that I find to be of use when searching for a service.
When I first meet with a prospective client, I often find them on LinkedIn before or shortly after our first meeting---then I connect with them and give them a way to see the quality of my work without bombarding them with samples. Works for me!
