By Robert DiGiacomo, for Yahoo! HotJobs

The invites to join BeKnown, LinkedIn, Facebook and other social networking sites are flooding your inbox from friends, colleagues, ex-coworkers, college classmates and even your boss. Do you accept them all or weed some out? And how can you build upon these relationships to advance your career?

Like much of our virtual existence, the rules for online networking follow those of the real world: Follow-up is key, flattery works and don't put something in writing if it could hurt your prospects.

Networking Made Easier

Adding online contacts is just the first step of networking -- you must also keep in touch with them, says Alexandra Levit, a career consultant, blogger and author of They Don't Teach Corporate in College.

"Mind your networks, and make sure you're using them to keep track of people," Levit says. "One of the biggest mistakes is to make a valuable contact and let it drop."

Maintain Distinct Identities

If you would rather your boss not find out the details of your Cinco de Mayo fiesta, separate your virtual personal life from work via dedicated social networking pages, according to Anastasia Goodstein, founder of the YPulse.com blog and author of Totally Wired: What Teens and Tweens Are Really Doing Online.

"Tell your boss you're setting up a page for professional contacts -- here's the link and 'friend' me there," Goodstein says. "Find a way to do it graciously, but keep it separate from your personal page."

To avoid having to maintain multiple social-networking profiles, you can set up one profile on Facebook using the BeKnown app. BeKnown lets you build a professional network on Facebook while keeping personal and work-related contacts completely separate.

Invitations and Recommendations

Rather than rejecting an unwanted "friend," accept the invite, but limit your interactions. "Just accepting them as a contact isn't going to do you any harm," Levit says. "Where I would draw the line is writing any kind of recommendation or endorsement of that person."

Use social networks to garner recommendations, and strengthen ties to business associates and colleagues by posting referrals for them.

"Nothing will endear you to the person more than telling them what you think of them and doing something nice," Levit says.

Keep It Confidential

Check your company's privacy policy before conducting certain kinds of business on a social network. Many companies are using search engines to monitor blogs, so watch what you say and where you say it.

"If you're talking about your top-secret product with a coworker on Facebook, I'm sure the IT department won't be very happy," Goodstein says.

At the same time, Goodstein adds, employers should spell out what's appropriate for chatting or blogging -- and what's meant for internal correspondence only.

Context Is King

When posting personal information or photos, leave out any revealing images, references to drug use or material that might be considered politically incorrect. "Don't have anything on there you'd be embarrassed to have grandparents or religious officiants see," Levit says.

Managers shouldn't automatically discount a candidate with a questionable photo or posting, depending on whether the material violates company policy or can be chalked up to a youthful indiscretion.

"It's a great opportunity to ask them about it in an interview," Goodstein says. "Younger people have been online for most of their lives, so it could be something they posted 10 years ago, but they've probably evolved since then. You can tell by how they answer if somebody's going to be a good fit."