49. Nextdoor

A social network for neighborhoods

Nirav Tolia, co-founder and CEO of Nextdoor
Source: Nextdoor
Nirav Tolia, co-founder and CEO of Nextdoor

Founders: Nirav Tolia, Sarah Leary, Prakash Janakiraman
Date launched: 2010
Funding: $110 million*
Industry disrupted: Social media

Remember when you knew all your neighbors and could get the name of a good plumber or babysitter from them? Well, Nextdoor wants to provide that service—21st-century style. The San Francisco-based start-up is a free, private social network for neighborhoods.

Nextdoor limits communication to the people who live in a particular neighborhood (you have to provide your name and address when signing up). Once on, residents can post information about what's going on in town, ask for help finding a specific service or offer things for sale. So far, the company has nearly 60,000 neighborhoods across the country signed up, representing 35 percent of U.S. neighborhoods.

Read MoreFULL LIST: 2015 DISRUPTOR 50

The plan is to leverage the trust built up in micro-communities to attract local businesses and services to advertise on the site. Investors see the promise in this hyperlocal concept. The company, started in 2010, has attracted $110 million in venture financing from Benchmark, Greylock Partners and Tiger Global.

*UPDATE: Funding level as of March 1, 2015, the data we closed the nomination process for the 2015 CNBC Disruptor 50. Nextdoor closed an additional funding round on March 4, bringing its total as of publication to $210 million.

"[Our disruptive impact] is measured by neighborhood adoption across the country. Nextdoor is now relied on by more than 60,000 neighborhoods, which represents more than 35 percent of neighborhoods across the U.S." -Nirav Tolia, co-founder and CEO, Nextdoor

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