I've been in the work force 12 years and had 4 jobs. My first job was my University Co-op that turned into full time employment after I graduated. When I want to change jobs I put the word out to my friends and ex-coworkers that I'm looking. Usually somebody will come up with something fairly quickly. I may or may not have to send a resume. The interview will be a formality. I've never just applied for jobs that are posted, that's what some of my friends are doing now and it seems very difficult, especially if you don't interview well.

I didn't even do anything particular to build my network. I just worked at a company with fairly high turnover for 4 years, so now I have ex-coworkers at pretty much every company in town.

I live in a fairly small city, 350,000 people. So it's pretty easy to get known in the tech industry without knowing that many people.