Next Big Things?

The scene is flooded with dynamic apps and services. Here is a list of companies that have the potential to become hugely popular

When Facebook bought Instagram for $1 billion last month, it raised questions about which start-ups might be on track for similar success. The scene is flooded with apps and services that are attracting users. But it can be hard to work out which companies are worthy of the kind of attention Instagram was receiving when Facebook came calling. Here is an incomplete list of companies with the potential to be a hit — whether because they've seen explosive user growth, or are attracting investors. Of course, any of these start-ups could become the next Pets.com. But they could also be the next big thing. — Jenna Wortham, Nicole Perlroth/New York Times

TaskRabbit
It sounds like an unlikely concept - people letting Internet-sourced strangers rent out their spare bedrooms or relying on them to run errands. But several start-ups are built on the idea that a new economy is being forged around "collaborative consumption". TaskRabbit, a service that lets people find "rabbits" to perform tasks is one rising star. Other potential contenders in this category: Skillshare, which lets people teach workshops, and Getaround, for renting cars.

Pinterest
Two years after it hit the Web, Pinterest, a kind of virtual pinboard, is the third-most popular social media site, after Facebook and Twitter. Users can "pin" images they find on the Web, say of a wedding dress or a tasty-looking dish so that they appear on their Pinterest pages. Other users can click to visit the source of the image. Pinterest still has a business model to figure out, but investors are intrigued by the site's demographics; women, who are big online shoppers, account for 85 percent of its traffic.

Dropbox
This file-sharing service solved one of the biggest headaches of our time: How to access files, photos and music across a myriad devices? Dropbox made it possible to store digital clutter in the cloud. Last year, the service had 50 million users, up threefold from the year before. Steve Jobs tried to acquire it in 2009 and, when that failed, introduced Apple's iCloud storage service. Google too introduced Google Drive. Dropbox, and its investors, seem confident it can go it alone. Last October, it raised $250 million in a round of funding that valued the company at $4 billion - or four Instagrams.

Quora
This question-and-answer Web site is everything Ask Jeeves never was. Questions range from the silly to the serious. Founded by Adam D'Angelo and Charlie Cheever, two of Zuckerberg's early employees at Facebook who kept that site from crashing. Investors are optimistic. The company, which has raised $11 million from venture capitalists, is now said to be raising more cash at a $400 million valuation.

Path
When Path was first unveiled in 2010, people scoffed at the idea of a mobile social network that only let users share with a limited number of friends. But as Facebook and Twitter have swelled in size, the appeal of privacy with an intimate few has begun to look more attractive - to users and venture capitalists. Dave Morin, Path's chief executive, has said that more than 2 million people have signed up for the service, and this spring, Path raised $40 million from financiers, pushing the company's value toward $250 million.

Pinwheel
Pinwheel, a service that lets you leave virtual notes tied to particular spots on the globe, like the best place to watch a sunset, may not seem like a sure bet. It's not clear yet whether the service, which is still in invitation-only testing mode, will spark excitement beyond the early adopters. But the founder, Caterina Fake, has a compelling track record. She was a founder of Flickr, and one of the founders of Hunch, a recommendation service, which eBay bought for $80 million last year.

Airtime
Not much is known about the latest venture from Sean Parker and Sean Fanning, co-founders of Napster, the infamous music-sharing service that shut down in 2001. The two men referred to their new company as a video-sharing site during a recent interview at South by Southwest, but the details are still under wraps.
With the current funding frenzy around video-sharing apps like Viddy and SocialCam, it is clear that Silicon Valley sees video as the next frontier. Airtime has piqued the interest of Adam D'Angelo, one of the founders of that other potential big hit, Quora, who was an early investor in Instagram. "It could wind up being really, really intriguing," he said.