Neighborhood social networking service Nextdoor.com rolled out home improvements on Tuesday along with word it is flush with new funding and eyeing community-minded cultures around the world.

Launched in late 2011 as a modern variation on town squares where people get to know neighbors and catch up on local news, Nextdoor has taken root in more than 8,000 US communities and is adding nearly 40 neighborhoods daily.

"Neighbors really do want to bring back a sense of community," said Nextdoor co-founder Nirav Tolia.

Nextdoor is about matters such as finding babysitters or gardeners; getting rid of unwanted skis; finding out when a pothole will be fixed; tracking lost pets, and checking out suspicious activity.

"It doesn't mean people want to be friends with their neighbors, you do that on Facebook," Tolia said. "Now is the time for technology to play a real role in connecting the neighborhood."

Nextdoor is free. The only caveat is that users must verify who they are and that they live in the real-world location that comports with the boundaries of the online neighborhood they wish to join.

Watching how people are using the service inspired improvements that Tolia referred to as "Nextdoor 2.0."

Neighbors linked together online at Nextdoor exchange about a half-million messages daily, with a fifth of those said to involve concerns about crime and safety.

Nextdoor upgrades include a section dedicated to neighborhood safety and ways to get text message alerts about crimes, fires, police activity or other public safety emergencies.

"We hear stories of neighbors not only preventing crime but actually helping capture criminal because they communicated," Tolia said. "The service has started this notion of a virtual Neighborhood Watch."

Nextdoor.com was "redesigned from scratch" to be more intuitive for visitors and optimize layouts for smartphones or tablets as well as Web browsing software used on desktop or laptop computers.

The San Francisco-based startup announced that it has raised $21.6 million in a new round of funding led by Greylock Partners, which was an early investor in Facebook and career-oriented social network LinkedIn.

"We feel now we can build a similar company to Facebook and LinkedIn," Tolia said.

Nextdoor, which has yet to generate revenue, raised $18.6 million in funding in July of last year.

Tolia envisions eventually tapping into the massive local advertising market in the United States, with marketers reaching people where they live.

Nextdoor has hired a vice president to oversee its international expansion, which Tolia said would begin this year. The roster of backers includes investment arms for Google and Amazon.com founder Jeff Bezos.

"Wanting to connect with neighbors is not uniquely Silicon Valley or the United States," Tolia said.

"This year, we absolutely will be in other countries," he continued. "Our foreign opportunity is probably better than in the US, because older countries tend to have a deeper ethos of neighborhood."