If you have a job and use e-mail, you've likely received an invitation to join someone's network on LinkedIn.

If you've ignored the invites, think again. Career coaches, marketing experts and those on the prowl for a new job say it's the hottest way to network.

And it's much different than MySpace or Facebook.

You won't find albums of pictures from girls' night out, bands trying to add you as a friend or requests to become a zombie.

LinkedIn is sleek, streamlined and, for an online networking site, downright private.

Founded in 2003, LinkedIn now boasts 20 million members that have posted their professional profiles, resumes and business contacts to the site.

Think of it like the game Six Degrees of Kevin Bacon meets an old-school Rolodex online.

Michelle Beckham-Corbin of Ohio is a big fan of LinkedIn. Through it, she found Brian Siegel, a fellow graduate of Xavier University's MBA program. He's writing a leadership textbook with one of her former college professors.

She found a link to Siegel's blog, sent him a message and soon the two started talking. Now, Beckham-Corbin is contributing an essay to the textbook.

"It's like an adult Facebook or MySpace," Siegel said.

When you sign up, you create a profile, which is like a condensed resume. Former colleagues, clients and partners can search for you, and you can ask contacts to join LinkedIn and connect to you.

You can view your contacts' networks, but you can't add someone to your network without their consent. And you have to confirm how you know someone before they're added to your network.

LinkedIn opened up last year to developers — the creators of Scrabulous, Food Fight, the SuperPoke and the other applications that clutter some social networking sites. But LinkedIn is keeping its focus on professionalism.

The site allows groups, but they're mostly for industries, corporations or universities.

In November, self-proclaimed "LinkedIn evangelist" Jennifer J. McClure started a group for Cincinnati-area members. At first, McClure got about 10 requests to join a day. Now she gets 70 to 100 requests a day.

Linked to a Yahoo! Group, LinkedCincinnati lets members post resumes, along with job openings and inquiries.

"I'm a big fan of LinkedIn," said McClure, who has more than 500 connections. "I've been able to facilitate connections for myself and others."

McClure — vice president of a recruitment and coaching firm — said she's gotten business from LinkedIn and tells her clients to use it.