A person's "network" is a collection of relationships that they maintain. Why, then, is it permissible to say you're "networking" when you have no intention of renewing the contacts you make?
I co-organize a blogging group and my wife co-organizes a wine tasting group. I meet a lot of new people every month. I *like* to meet new people. It's OK if I learn someone's name and occupation and then never see them again; my groups aren't for everyone. But if you come to an event and hand out your business card to everyone there, then a couple months later when nobody's heard from you I'm going to start thinking you came for the wrong reasons. That you came to promote yourself and not to take part.
Now don't get me wrong - it's OK to accidentally come to an event for the wrong reasons, but once there, you should recognize your mistake and adjust your approach. You don't create a positive personal brand when you drop business cards like propaganda pamphlets out of the back of a plane over enemy territory.
This is related to how permission marketing can be overused. But whereas that was about people who abuse my attention with a one-way firehose of marketing, this is about people who come to meetings--all kinds of meetings--with no intention of doing anything but broadcasting a single message. I'm convinced that some of these people scour the Internet for every public gathering where they might meet a couple dozen people in a free evening. People that may turn into leads, and if they don't, they don't matter. They are serial self-promoters.
Networking shouldn't be that way. When I check out a new group, I'm trying to see if there's a place for it in my life. Sometimes there is and sometimes there isn't. If I keep coming back, I don't even bother to call it networking, I just end up getting to know people. And that ... my friends ... is a network.