My thoughts on this topic - which Chris summarized well in the post - are further articulated in the Do I need an Advisor post I made recently. As a startup, you want to know that when someone makes an introduction, they are taking it really seriously. Access to a "contacts list" shouldn't be based on money (at one extreme) or "sure, I'll do that for you," (at the other) but really based on you, the startup, earning it. You want someone who is focused, dedicated, and willing to say "no, you are not ready" when you are not ready.
Honestly, this seems awkwardly self-promotional to me, but I really believe in this meta topic (the rise of an unqualified "Advisor class" in Silicon Valley) and it's micro topics, such as introductions.
The post is here and the you tube video is embedded below.