That's why Lauren Miller, who was laid off in October, is so vigilant with her Facebook profile. She watches for any photos friends might post showing her holding a drink. Off-color comments by anyone are immediately deleted.

"You never know how things will be perceived," said Miller, a resident of Hoboken, N.J., who worked in corporate communications.

At times, she wonders if a recruiter needs to know that she's 36, single and Jewish before she walks in the door for an interview.

Social-networking sites typically let you post as much information about yourself as you like, including your education, work history and favorite music and books. You can join countless fan groups or causes. Status updates, which tell how you're feeling at any moment, offer yet more clues about you.

How much you should reveal varies depending on your situation, of course.

In some creative fields, showcasing a quirky sense of humor might score you points. Your love of marathons might even get you in the door with certain hiring managers.

The bottom line is that if you're looking to land (or keep) a job, you need to treat your online profile like a resume - keep it scrubbed and up to date. A few points to remember:

Who can see my profile?

One of the first steps in staying on top of your online profile is being aware of the privacy settings.

Facebook, for instance, lets you join networks that tie users with a common bond, whether it's a company, school or where you live. You need a valid e-mail address to join the first two types of networks, but anyone can join a regional network.

The default setting on the site lets friends and everyone in your network see your profile.

If you're not comfortable with this setup, you can tweak settings to control who sees what. You can even decide which friends can see select photos.

"If you have your privacy set properly, you really are controlling every aspect of how your profile is viewed," said Brandee Barker, a Facebook spokeswoman.

That said, it's always safer to assume anything you post online can become public. After all, Facebook has more than 140 million registered users, although the company doesn't disclose how many of those are in the United States.

How personal should I get?

There's nothing wrong with revealing your love of biking, dogs or Malcolm Gladwell books. But even if you set up a profile for personal reasons and don't intend for potential employers to see it, there's a good chance they'll search for it.

A member survey by the Society for Human Resource Management last year found 34 percent said they use social-networking sites to recruit potential applicants, while 19 percent said they plan to.

Of those who used social-networking sites to screen applicants, 47 percent said did so before contacting the applicant for the first time.

"If a recruiter comes across your profile, there's a risk they'll judge you based on information that's not relevant to your job," said Alison Rosenblum, co-owner of Strategic Resources, a recruiting firm in Albany, N.Y. "It shouldn't be relevant, but it is."

Still, it can work in your favor to share your interests online.

Even LinkedIn, a social-networking site designed specifically for professionals, includes a field where users can list interests. The idea is that such personal details can help forge bonds in the professional world. It happens all the time in face-to-face interviews; people click over a shared alma mater, hometown or hobby.

What are potential pitfalls?

There are a couple rules to remember if you're using a social-networking site specifically to look for a job.

To start, don't bother posting the vacation, party or new baby pictures. Limit your photo to a recent head shot. It should resemble a picture you'd see on an executive bio.

Another mistake people often make on LinkedIn is listing only their current job, Luo said. Listing all your experience gives recruiters a better sense of your abilities and widens the chances that you'll get a nibble.

There's also a reason LinkedIn doesn't have fields for religious and political views. Companies can't turn people away for political or religious reasons, but they're sensitive topics better left to your personal life. In some cases, publicly stating such views might interfere with a company's mission. If you're unsure about whether to include certain details, a good barometer is ask whether you'd list it on a resume.

Where do I draw the line?

You might feel more relaxed about what you post if you're employed and comfortable with your boss and co-workers. But airing personal details about yourself online can still affect your work.

Even if nobody at the office cares that you're a die-hard Democrat, a potential client might.

Also, consider how loudly you should advertise where you work in your online profile if the account is primarily for friends and family. Your company might not mind workers broadcasting views online, but it also might not want to be publicly affiliated with them.

This article appeared on page C - 4 of the San Francisco Chronicle