Remember the days when a glance at a paper résumé was all a recruiter needed to decide whether you were getting an interview? Today, social media have us connecting, networking and promoting ourselves in an instant, allowing prospective employers to do the once-over even quicker.

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And that's a good — and bad — thing, too.

It's good because employers understand the power of social media to advance their businesses. If you're an active participant online, it's all the better to show how connected to the times you are. You can use these digital platforms to highlight your personality and qualifications to show what you could bring to a workplace.

But, as becomes clearer by the day, what you put out there can come back to bite you. Employers can use social media platforms to learn things about you that you'd rather they didn't know.

So if you're on the market for a new gig, your first task is to type your name in quotes into a search engine and see what pops up. If you get a photo, video or anything else that you wouldn't want a prospective employer to see, get to work on removing it from wherever it's posted.

Then focus on figuring out how to use social media in a positive way to lead you to your next opportunity. Here's a guide to the three most popular sites Facebook, LinkedIn and Twitter — as well as tips for creating your own personal place online.

Facebook

With 900 million users, Facebook is the shining star of social media. And boomers account for a growing number of its fans, using it to maintain connections with friends and family members. But being careless with the information you share on your personal profile could push your résumé to the bottom of the pile.

"At the end of the day, your profile is your life and it should be as public or private as you want," says Beth Carpenter, social communications and strategy manager at AARP. "But realize that once you put something out there to the public, it's out."

Next: 8 ways to save face on Facebook »