In order to get results when networking online (for example, on LinkedIn) as well as offline, you need to take into account some fundamental principles. To be a really successful networker, adhere to the "golden triangle" of networking.
The three points of the triangle are:
1. Give or Share. Ask yourself what you can give or share with other people. One of the best ways to build a relationship with someone is to share something. For many people this is a hard concept because they think in terms of lack rather than abundance. They may think that if they give something away, they no longer have it themselves.
Though that might be true for physical objects, we live more and more in a knowledge society (especially in the Western world). When you share information or knowledge (like I'm doing with you now) you don't lose it. We both get to benefit from having it.