Neighborhoods are taking shape online as Internet companies expand the capabilities of local search.

Neighborhood-specific searches allow users to move beyond the typical geographic parameters of city or ZIP code to find relevant matches, though defining neighborhood names and boundaries can be an imperfect science.

Yahoo! in August announced the launch of a "search by neighborhood" feature for major metropolitan areas, through Yahoo! Local. It is now possible to search for real estate agents in San Francisco's "Lower Haight" or "Marina" areas, for example, or in New York's "Chelsea" or "Soho" neighborhoods.

Yahoo! Local has divided San Francisco into 31 neighborhoods, and New York City into 24 neighborhood areas.

Other online sites, too, provide neighborhood-specific information to users, and experts say real estate is a natural beneficiary of neighborhood-based search.

As some print advertising dollars shift online, the battle has heated up among online search sites to tailor information and advertising opportunities based on the criteria selected by users. Local online search has grown into an important subset of national search – an estimated 15 percent of all searches on the Web are local – and neighborhood search is an emerging subset of local search.

"There are a lot of people who recognize that the way that people look for things is by neighborhood or by colloquial names that exist," said Greg Sterling, program director for The Kelsey Group, a company that provides research and analysis for yellow pages, electronic directories and local media companies. The end result is more flexibility – and less search time – for users.

"What's at stake? Better ad targeting and the ability for advertisers – especially in the real estate context – to buy keywords aligned with neighborhoods, which is the way people really think about their environments in the real world. Accordingly, this will offer a better local-search consumer experience," Sterling said. "This is definitely the way these things are going to move – (companies) are trying to make these tools conform to the way that people really live."

Sterling also said that Yahoo! is a front-runner in neighborhood-specific searches, and the company's announced plans to acquire Whereonearth, a local online search and advertising technology company, should aid the efforts to expand local search.

Point2 Realty Solutions, a real estate technology company based in Saskatoon, in the Canadian province of Saskatchewan, is working to define neighborhood names and boundaries to provide more property-search options. The company's Point2 Homes site allows users to search properties by neighborhood.

"Our goal is to geographically identify every area in North America, and then eventually the world, by its local neighborhood names," said Jeff Tomlin, manager of market research at Point2. The company started the project this summer.

Local municipalities and real estate professionals have been a solid source of information on neighborhood names and boundaries, Tomlin said. "The solution we are building has two benefits: Number one, we want to create a solution for our members that helps them be more easily found; and we are helping our users to create a better connection to consumers."

Point2's real estate customers are accurate in describing the neighborhood location of properties that they list for sale, Tomlin said. "The client knows exactly what neighborhood they're in, even if they're sort of on the edge of two neighborhoods. Our members are the best sources for that – they know the area themselves."

The neighborhood project "is a work in progress – it'll be a work in progress for some time," he said, adding that neighborhoods are continually evolving and forming.

Craigslist, which operates online community sites in major markets across the globe and carries for-sale and rental property listings posted by its users, allows users to self-identify location by neighborhood. A user who wishes to post a property for sale in San Francisco, for example, can choose from a list of 32 neighborhoods, and the neighborhood name appears in the top line of every posting.

The New York Times' real estate site allows users to search for properties by neighborhood areas, and several other property-search sites also offer neighborhood-specific listings.

Keith N. Hampton, assistant professor of the Annenberg School for Communication at the University of Pennsylvania in Philadelphia, said that Internet technologists are struggling with the same questions about neighborhoods that sociologists have been struggling with for decades, adding that it's "fascinating" to see efforts to expand local and neighborhood search capabilities online.

"Defining neighborhoods is certainly difficult and problematic. What are neighborhood boundaries for any given neighborhood? It is almost impossible for outsiders to define boundaries in a way that makes sense (for local residents)." Every person has a mental map of neighborhood areas, Hampton said, so it is typical for people to disagree on neighborhood boundaries.

Hampton is a principal investigator for I-Neighbors.org, an Internet site that allows residents to define neighborhood areas and connect with their neighbors.

It's beneficial for actual neighbors to define neighborhood boundaries, he said, because it is a means to "establish local trust in self and identity – being able to identify what your community really is. The value of the Internet is supposed to be in its ability to cut down the cost of traversing great distances. But it has this localization – the ability to bridge very local distances."

He noted that neighborhood boundaries change, and in some cases some small neighborhoods can potentially be amalgamated or absorbed into a larger neighborhood area, and can lose individual character or identity in the process.

Wikipedia, a free encyclopedia Web site that allows its users to edit entries, features numerous neighborhood descriptions, including rough or specific neighborhood boundaries.

Jimmy Wales, a spokesman for Wikipedia, said he doesn't know how many neighborhoods are defined at the site, though, "Community input would be crucially important to determining where a neighborhood begins and ends, because 'neighborhood' is absolutely a social concept, a social construct, and there's no a priori or algorithmic way to guess at it."

"I think everyone in New York defines neighborhoods in slightly different ways. Some neighborhoods are literally defined by a couple of blocks," said Lockhart Steele, founder and publisher of the Curbed.com blog site.

Curbed.com readers can choose to read postings that are specific to neighborhoods. The site identifies 14 Manhattan neighborhood areas, for example, and also includes information categorized by neighborhood in Brooklyn and Queens.

Earlier this year, Curbed.com hosted a light-hearted neighborhood-naming contest, dubbed "'Hoodwinked." The winner pitched the name "RAMBO (Right After the Manhattan Bridge Overpass)" for a neighborhood stretching between Tillary Street and York Street, north of the Manhattan Bridge.

There is a general trend, Steele said, to provide more focused information online. "You can always get more detailed. There is the question of: 'Do readers want to view everything?'" For editorial purposes, Steele said that he adopted fairly rigid neighborhood boundaries for Curbed.com.

"I think neighborhood-specific search...is going to be a pretty big deal," and real estate companies have already inquired about placing advertisements on neighborhood-specific pages at his blog site, Steele said. "Drill-down search is presumably one of the better ways to find really qualified leads." While neighborhood search is one potential avenue for expanding local search capabilities, Steele said innovation in search technologies is not a one-way street. "I don't believe search is moving in any one direction.