Excerpt from book "10 Secrets to Networking"
Secret #2 Psychology of Networking 

Networking requires that you give before you get.  This is essential for true success at networking. It is key to "walk the walk" as well as "talk the talk." If your sole purpose for networking is to be helped and not to help, networking will not work for you. In order for networking to be effective, you must take the stance that everything you do has a reciprocal effect.  Hence when you give, others give back to you. It is also important to remember that your referral does not have to come from the exact person to whom you gave a referral.  This basic understanding is required of those who are to be succesful at networking.

The psychology states that if you look for opportunities where you can share information with others, others are also looking for opportunities where they can share with you. Put information into your networking bank account and you will have dividends to withdraw!  This is how finance works in general. When you go to the grocery store to buy bread, do you walk to the counter and say, “give me bread,” and get it? No, you are required to give something first and then you get the bread in return.  The law of give and receive is basic to the psychology of networking and is even more evident when one tries to turn your networking efforts into cash.