Americans have lost touch with their neighbors, but one company is looking to restore the country's sense of community through social media.
"Nextdoor is a very unique social media site," CEO Nirav Tolia told CNBC on Thursday. "It's not about connecting to your friends, it's about connecting to your neighbors."
He cited a statistic that almost a third of Americans don't know a single neighbor by name. "There's so many ways our neighbors can help us," he added, "and technology can play a role in bringing back the sense of community to the neighborhood."
Nextdoor can be used to find a babysitter, track down a lost pet and even apprehend potential burglars. "Many times users have used NextDoor to warn each other about suspicious activity and either prevent or at time apprehend criminals that are trying to cause mischief in their neighborhoods," he said.
Tolia said that 100,000 messages each day on Nextdoor are related to crime and safety. "We live in a world where local governments are under budget pressure and we need to find ways to use technology and social media for safety and crime prevention," he said.
With the service now in 8,000 neighborhoods, Tolia said, "it's all about connecting and communicating with the people around you."
The company, which launched in 2011 and has raised $40 million in financing, has some high-profile backers, including Google Ventures, Allen & Co. and Greylock Partners.
On Wednesday, Nextdoor announced $21.6 million in financing that the company plans to use for market and platform expansion.
Greylock's David Sze, an early Facebook investor, told CNBC last month, he's been a big fan of the company saying it uses the Facebook experience to bring back person-to-person interaction and trust in neighborhoods.
"All that benefit of the neighborhood you used to have that has been lost over the years, we're now using technology to bring it back," Sze said.
Tolia sees opportunity in local advertising, which he said is a $100 billion market. "But all of the ways people advertise locally today appear to be on the decline," the CEO said, citing the decline of the Yellow Pages, local TV and local newspapers. "We believe that spend will come on line and when it does Nextdoor will be a great place for that to take place."