, a for-profit social-networking site, and the Nutter administration announced a partnership Thursday that will enable the city to communicate directly with Nextdoor's 17,000 local users.

It will allow the city to more narrowly focus its online interactions with residents who belong to the online network.

The Streets Department, for example, will be able to send a notification of a street closing to residents in the affected neighborhoods.

"This offers us a cost-effective method to communicate with residents in a targeted way," Managing Director Rich Negrin said. "It is a powerful tool to target specific messages to specific neighborhoods."

The partnership is similar to ones has struck in communities around the nation as it tries to attract a broad base of users in anticipation of raising revenue through ads.

The city's partnership, which gives Nextdoor users unique access to communications from city departments, will increase Nextdoor's value by enabling it to attract more residents to its site.

The city will receive no payment in return.

"It adds value for our citizens," Negrin said. "This enables them to have greater access to services. We think that is enough." is an online social-networking site much like Facebook but targeted to neighborhoods. Individual neighborhood sites are free to anyone who can verify that he or she is an area resident.

Members can use the site to communicate with one another, engage in local online forums, discuss neighborhood issues, and seek recommendations from neighbors for babysitters, contractors, and other services.

According to Sarah Leary, cofounder of the San Francisco-based Nextdoor, the company maintains 283 neighborhood sites in Philadelphia. The sites cover about 80 percent of the city, she said.

The networks are private to their members. The partnership announced Thursday will allow the city to communicate directly with network users. Participating departments include the Office of Emergency Management; Streets; Licenses and Inspections; Town Watch Integrated Services; and police.

Deputy Police Commissioner Nola Joyce said the network would allow local commanders to "meet virtually" with Nextdoor users who might have missed a public meeting held by the department.

Nextdoor was launched in 2010. While it has yet to make a profit, it has been kept afloat by more than $100 million from investors. Based on that level of investment, Bloomberg News estimated the company's value at $500 million.