What to do if your networking contacts don't reciprocate

Here's the situation: You're a diligent and thoughtful net worker, trying at all times to help your networking contacts with introductions and contacts. When you can do so, you make direct introductions to potential clients; at other times, you help people get connected to other influential connectors and referral sources. You're fairly diligent about it, and not a week goes by without some sort of introductions being made.
And you don't except anything in return. Well, not really. So, does this describe you?
If so, then you know that at some point you might want/need to be so forthright as to ask some of your networking contacts for specific introductions for yourself, maybe not to a specific company but perhaps to a suitable category of business.
You make your request in person or perhaps through email or the phone. And nothing happens. The request is either totally ignored or the person says that they'll "get back to you with some names and introductions." And again, nothing happens. What's a net worker to do?
I get asked this question quite often and this same situation has even happened to me causing me to ponder the next steps. Here they are:

• Make certain that you have made your initial request loud, clear and unambiguous. This is not the time to be coy; make sure that your request for contacts leaves nothing to the imagination.
• Be sure that you haven't asked for introductions or connections to folks with whom your networking contact has absolutely no involvement. Be confident that the person that you are asking does, in fact, have the desired relationships.
• Give the person a wee bit of time. While we live in an era of "Internet time" not everyone moves at the speed of light and your request might languish for a few days or weeks until such time as it rises to the top of the "to do" list.?

If you have done the above and are still not receiving the introductions that you feel "should" be coming your way, you can do the following:

• Make your request again and ask the contact for the reason(s) that the intros are not forthcoming. Do this gently as it might be uncomfortable and, even if you believe this person has not risen to the networking "occasion," they are still in your networking circle of contacts and you want to maintain a positive relationship.
• Move on and forget about it, realizing that not everyone is as receptive to the idea of making introductions for others.
• Think about whether there are any unspoken or underlying reasons why the introductions are not being made. Does this person have a better relationship with someone else that does exactly what you do? Have they ever been "burned" by an introduction and therefore are loathe to feel that vulnerable again? Do they not respect the quality of your work? Be honest with yourself!

Most of all, don't let the unresponsive folks "get you down" and cause you to lose your enthusiasm and interest in helping others with introductions and referrals. While it might not always come back to you (even when you ask!), it's still the right thing to do.