It can be hard to meet your neighbors. They are coming, you are going. You can go months without ever seeing the guy in 4B.

For all you know, you might be living next door to a potential best friend, if only you had a way to start the first encounter.

Enter LifeAt, a new social networking service that is part community bulletin board, part Facebook.

Designed specifically for residents of large urban apartment or condo buildings, the site offers residents the chance to compare interests, share information about the neighborhood, find poker games, play groups and more.

“I don’t think it ever replaces face to face communication, but it gives people a comfort level to get to know their neighbors,” says co-founder Matthew Goldstein, chief executive officer of LifeAt. “How many times have you seen your neighbor in the elevator but you don’t say anything to them? People are a little bit shy, whether or not they like to admit it. They use our service to find out a little bit more about people.”

The service started in Manhattan and has now found customers among building owners and operators in eight states and three countries, but most of the users are in New York City and Florida. The service typically is contracted for by the building owner or management company as an added service for residents. LifeAt charges a flat $6,000 for each site. Building sizes range from 42 to 12,000 units, and while most are urban high rises, the service also has been used by a golf course community in Boca Raton, Fla.

About nine months ago, the company entered the Chicago market, and now is establishing sites for seven area buildings. Among its newer clients are 600 Lake Shore Drive, 340 on the Park and 565 Quincy.

Jon Zitzman, president of JFJ Development Co., developers of Superior 110, thought it would be a good service to offer potential buyers.

“It helps people feel more comfortable about their environment and meet others,” he said. “We saw it as the next progression.”

His building is more than half sold and at completion will have 77 occupied units. He felt that LifeAt offered the amenities that his buyers would want, and that it would be cheaper to buy than to design and manage internally.

Building owners have found it has two other practical uses as well. For one, it lets owners and renters complain in a space where the property manager can see it – and do something about it. “At first clients were reluctant to give residents the opportunity to speak to each other (and complain). But we said, ‘they are going to do it anyway.’ This way you can maintain it and react to their concerns.”

The other surprising advantage for building owners is that it can be used as a marketing tool. While part of the site is password protected for residents only, most also have a link that says, “I am interested in living here” that generates leads for sellers.

Goldstein said the service is more than just a bulletin board, though that is part of its appeal.

“This does replace the cork board in the laundry room,” he said. “You can buy and sell goods, advertise services and post wanted ads.”

But it’s different than a Craigslist or Ebay, because if you are buying your neighbor’s couch, you can go see it easily. Purveyors of personal services also can find clients right in their building, and residents, too, may appreciate finding an accountant or Realtor nearby. Residents also use the service to sell parking spots, find a baby sitter, exchange time shares and more.

Neighbors also use it to share information, Goldstein said. They post reviews of nearby restaurants, share information about dry cleaners, spas and hair salons.

While LifeAt’s early model was the urban high rise, Goldstein thinks it works even better in suburbia.

“In a high rise, you see each other in the elevator,” he said, “but across 50 different streets in Boca Raton, they may share the same golf course, but they never see each other in the lobby because there isn’t one.”