Job seekers know they're supposed to be tapping their networks for leads, but there is a good and a not so good way to go about it.

By Anne Fisher, contributor

FORTUNE -- Dear Annie: I'm hoping you can clear something up for me. I've been looking for a job in project management for the past several months, after taking "early retirement" as an alternative to getting laid off, although I can't afford to retire yet.

I keep hearing that I should be contacting everyone I've known in my career to ask if they know of any openings, since the best available jobs (especially management positions) aren't advertised anywhere. So I've been doing that, but it's getting to the point where people aren't returning my phone calls or answering my Tweets anymore, and I feel like I'm wearing out my welcome. Do you or your readers have any suggestions on where to go from here? — Outside Looking In

Dear Outside: No doubt about it, in this economy, plenty of well-connected people have come down with an ailment you might call networking fatigue.

"If you contact someone in your network and that person seems not to want to talk to you, then it's the wrong person," says Jonathan Kreindler. "He or she is probably hearing from too many job seekers, and they're all after the exact same information about current job openings." More