I found my first job with the help of an on-campus recruiter, and with a local Boston-area recruiter. I found my second job through the newspaper. I've found all my other jobs (all of them, including my consulting engagements) via my network, which does include recruiters. That's about 25 years of jobs.
Louise Fletcher has a great post about companies responding to online applicants, Is there Anybody Alive Out There? Sure, companies are not responding, so what's a candidate to do? Network.
Candidates: Let me echo Louise's advice: If you're not on LinkedIn, join now. Stop reading and go there, join, fill out at least part of your profile, and then come back here. Find the people you've worked with before, invite them. Recommend a few of them. The more you recommend, the more likely they are to recommend you. (I'm not affiliated with LinkedIn. I receive no money from this endorsement.)
Is this a pain in the tush? Yup. And, it's worth it. I know that some of my recommendations have made a difference in people calling me for consulting engagements.
If you've been working for more than 3 or 4 years, you'll need your network just to find good recruiters, if that's one of your job-seeking strategies.
Hiring managers: If you want the ability to know a little about a candidate before you phone screen or interview them, or if you want to do a behind-the-scenes reference check, you need to be on LinkedIn also.
I don't recommend Facebook or Myspace for professional networking. You can't see the connections or recommendations. My kids use Facebook to post pictures and gab with their friends. It's for social networking, not for professional networking. No, I'm not friends with my kids. That's just wrong. But when they graduate from college and are ready to increase their professional networks, I will connect with them on LinkedIn, offering them the use of my network.
You need to be ready to offer something to your network connections, and a recommendation is a great way to start.
It's rare for a more senior person to find a job without networking, so make sure you pay attention to your network (whether you are looking or not), and manage it.