I would imagine that networking in writing is like networking in any other field: it's very important for a variety of reasons. I'm not big on writing conferences (I'm an academic and spend enough money on conferences as it is), but I've found other forms of networking to be incredibly valuable. I've made plenty of new beta-reader and critique swap friends, shared information about querying and publishing, compared notes on experiences with agents and publishers, etc, etc, etc. So I wouldn't think of conferences/networking as solely being about getting an agent.
On the other hand, several writers I've connected with got publishing contracts or an agent through knowing other writers. Social networks (in the sociological sense; not talking Facebook here) are extremely powerful tools. Part of the value of an MFA is the networking, in my opinion. So I wouldn't discount networking/conferences as an important way to reach out to agents and publishers.
So, I guess what I'm trying to say is that yes you should be building your social network at conferences, etc, as a writer. It might lead to an agent/publisher, but most likely it will just make you a better writer and better at the business side. But you should also be doing the querying thing as hard and as well as you possibly can.
As has been said, there's no secret handshake. You have to write the best damn novel you can.