Investors eye alternative social networks Nextdoor has raised $21.6m in new funding led by Greylock Facebook and Twitter might have hundreds of millions of users, but some of their earliest investors are placing bets that they will not have the last word in social media. Benchmark Capital and Greylock Partners have this week invested substantial sums in a new generation of social networks that lack revenues but emphasise privacy rather than public sharing. Snapchat, a mobile app that destroys all photos and videos seconds after they are opened, and Nextdoor, an online community for offline neighbourhoods, have each attracted millions of users without using Facebook or Twitter integration to kick-start their social networks. Indeed, these companies are making a virtue of operating independently, as they seek to provide new services to those who may be wary or weary of Facebook and Twitter's noisy sites. "If you build something differentiated, there can be distinct social networks from Facebook," said Nirav Tolia, co-founder and chief executive of Nextdoor. Facebook is all about connecting with your friends. Nextdoor is all about connecting with your neighbours. Not too long ago that idea would have been given short shrift by many investors, as Facebook accumulated hundreds of millions of members and attracted thousands of apps that relied on its developer platform to populate their own sub-networks. Yet on Tuesday, Nextdoor announced that it had raised $21.6m in new funding led by Greylock, an early Facebook investor, on top of the $18.6m it raised from Balderton and others in July. The investment follows Snapchat's $13.5m financing earlier this week, valuing the Los Angeles-based start-up at up to $70m. Benchmark, which still holds a stake in Twitter, led the round for Snapchat, which is particularly popular among teenagers. Bill Gurley, a Benchmark partner, acknowledged that many social networks targeted at certain demographic or professional verticals have not done well, but added: "Twitter and LinkedIn were once called alternative social networks." He said the types of conversations that neighbours have on Nextdoor have a utilitarian nature distinct from other social networks. Neighbours, whose real names and addresses are verified by Nextdoor but kept out of search engine results, ask each other for recommendations for caretakers and other local services. They can organise to get a pothole fixed or address a local crime, or ask if anyone has a hoe they can borrow, with posts shown only to people in a defined local area. "These conversations aren't happening on Facebook," he said. This is not a dancing cat, or a picture of someone at a party. This is about improving lives in those communities. The argument for investing in alternative networks was bolstered by LinkedIn's earnings last week, which came in far ahead of Wall Street expectations. Yet the professional network remains one of the few internet companies to list in the past 18 months that still trades above its initial public offering price. The poor performance of Facebook, Zynga and Groupon stocks has prompted debate in recent months among Silicon Valley entrepreneurs and investors about whether start-ups targeting enterprise and business-to-business customers - which produce products companies will pay for rather than relying on advertising and eyeballs - might make better prospects for 2013. "We are almost 20 years into the consumer web and we have large platforms that are starting to suck up a lot of the oxygen," wrote Union Square Ventures partner Fred Wilson in a widely cited November blogpost. The wind that has been at our back for seven or eight years in consumer internet is no longer there. Some Facebook alternatives have prospered in the past year, including Pinterest, which is rumoured to be raising a new round at a racy $2.5bn valuation. However, others, such as Path and Foursquare, have attracted only niche audiences. Snapchat and Nextdoor are following in the tradition of their predecessors by focusing on attracting users before trying to make any money. For at least a few years we are going to focus on adoption. We know there is a giant pot of gold at the end of the rainbow," Mr Tolia said, referring to the $100bn local advertising market. Yet even as they invest in alternatives, some venture groups may be hoping that these companies are acquired before they ever have to worry about revenues, much as Instagram was when Facebook offered it $1bn last year, as established networks try to prevent their dominance from being undermined. Snapchat's "ramp" of user growth, wrote Benchmark's Mitch Lasky on his personal blog over the weekend, "reminded us of another mobile app Benchmark had the good fortune to back at an early stage: Instagram."