While writing Monday’s post on job interviewing, I ran across a U.S. News & World Report piece on finding employment through social networks. A quick search revealed a string of success stories about folks finding new jobs — sometimes only hours after being fired, CNN says — thanks to these sites.

Speaking of success, if there’s one Web site that’s benefited from ye olde recession, it’s LinkedIn. In March, CNN reported that year-over-year traffic to the professional networking site has doubled since February 2008. As layoffs continue, and thousands hunt for jobs, social media has been hailed as the 21st century résumé. A mere sampling of some of the more specialized networking outlets for particular industries includes Sermo (medicine), AdGabber (advertising), Epernicus (science) and Teachade (education).

But you can’t simply create a LinkedIn name and password and wait for the job offers to start pouring in. Building a professional network that could lead to employment takes some legwork. And since you’re probably chomping at the bit to get on your way to a new cubicle or corner office, here’s a handy list of Do’s and Don’ts:

•    Don’t Dive Right In: Create your profile and lurk around for a while. Figure out the site’s netiquette and how you want to contribute.

•    Do Participate in Discussion: Adding your two cents in group discussions and Tweets can showcase your professional expertise.

•    Don’t Overshare: Your social media profiles shouldn’t read like tell-all diaries. Remember to create a professional image or crank up security settings.

•    Do Cultivate Relationships: If there are people in your network you could benefit from professionally, consider what assets you have to offer in exchange. Avoid mooching.

•    Don’t Stop with Social Media: Mashable.com’s list of the Top 10 Social Sites for Finding a Job suggests starting a blog or personal Web site in addition to your profile. That increases your Web presence and further show off your skills.

Anyone had job luck with online networking? If so, tell me about it. Otherwise, happy hunting!

More on Social Media:
How LinkedIn Works
How Twitter Works
How Facebook Works
Can I make my living in Second Life?