The idea is that each neighborhood uses its own website to swap information about people, places and things, ranging from safety issues and lost pets to items to trade or sell.
The company said San Mateo County is the first county government to join the "private neighborhood website," and said cities such as Menlo Park have set up links, so that they, too, can make postings on local sites.
Nextdoor Communications Manager Whitney Swindells said for now the sites are just for residents, not businesses, with the exception of residents who do business in their own neighborhoods. Down the line, she says, the company expects to make money by working with local businesses to provide offerings to members.
When members first register, they set up a password and fill out a profile. "A hundred percent of our users use their real name and the street they live on," Ms. Swindells says.
"You don't necessarily want to be friends with your neighbors ... but you may want to be in contact," explains Ms. Swindells. Compared to Facebook, she sees Nextdoor as having "more of a utilitarian purpose."
Member Nadya McCann calls the website "essential" after going through a scary experience when her son suddenly came down with a contagious form of bacterial meningitis this past June. She used the website to post an alert to urge anyone who had had recent contact with him to go on antibiotics to prevent getting the disease. Some family and friends then heeded the advice.
She says she received a lot of helpful support from members in the form of e-mails and meals. Three months later her son has made "a full recovery" and recently competed in a rowing competition in Canada.
When Nicole Perkins moved to Woodside from Menlo Park, she says, she missed the sense of community that came with belonging to a mothers' group there. When she heard about NextdoorWoodside, she embraced it as a chance to engage in her new neighborhood, and invited 52 people to join, including the head of the PTA at Woodside School.
Jackie Ballinger posted a car for sale last spring and received no nibbles, but did find a used truck on NextdoorWoodside, a vintage typewriter, calligrapher, and a house. She says she read about an upcoming real estate listing, jumped on it, and will be moving in soon with her new husband, Kevin Killeen.