It's really important to really consider your market before going straight to Linkedin. If you're selling a service which is similar to many competitors, the top people you will find on LinkedIn are probably already aware or a customer of a competitor of yours, so your job just got harder using those leads. If not, you want to make sure that your audience is even on LinkedIn. For example, if you're selling products to machineists, scouting out people on LinkedIn will probably lead you to corporate people -- not the people you want to sell to. It can be very useful, but it isn't suitable for many purposes.