If you've lost your job, don't keep that to yourself. Think about all of those Facebook friends you've accumulated over the years. Sure, you might be annoyed by their occasional political rants or inane kitten videos, but one of these people might be the critical connection between you and your next job. Think about it: The people you are closest to will automatically help you if they can. It's the folks you may not ordinarily talk to in person that need a broadcast message.
Before you send out a mass Facebook or e-mail message saying, "I'll do anything!" consider a more strategic approach. People are more likely to take action if they have parameters. Be as specific as possible about the fields and job titles you want to pursue. Saying that you want to work in "organic agriculture" or "vegetarian catering" is much more effective than saying, "I want to work with food." By giving your contacts specific keywords, they can refer you to friends or companies who match those searches. The worst someone can do is ignore you (or defriend you), but you never know who holds the magic ticket to a great job opportunity.
This strategy can also work if you are starting a business – of course in that situation you should already have a clearly defined message (and hopefully a Facebook page for the business that you will invite friends to follow).
For lots more information about job searches and networking, check out the related HowStuffWorks articles on the next page.