The fact that you simply reached out to someone does not put them in your debt. No one is required to pay you back. Instead of approaching networking with the goal of gaining favors, try reaching out with curiosity. Contact interesting and relevant people and see what happens. Some of them will respond and some will not. Learn about the people that do follow up. Find out what make them interesting and how you can assist them. And do not expect anything in return…
I received a call from a contact asking me for assistance, not for business, but to assist someone that needed help. They knew that I am very well connected through out the country, and the individual was looking for something specific. I was honored that they remembered who I am and what I can do let alone provide through my business.
Simply, the way I look at it is if someone does get back with you and reciprocate, what a wonderful surprise!