Twitter no longer exists just for friends to tell friends that they’re on their way to the gym or out to eat. It’s become a kind of hypergrapevine news resource — a way of instant messaging your circle of friends about your interests (“Did you hear what Obama said today?”) or consumer rants and raves (“The customer service at Zappos.com rocks!”).

The service is even credited with breaking news about fires and other natural disasters.

Twitterers, as they call themselves, post their updates at Twitter.com or by using text- or instant-message tools.

A cottage industry of websites — including TweetScan, FriendFeed and Summize (which Twitter recently acquired and renamed Twitter Search) — have popped up to service the Twitterers and their tweets, by making it easier to search through the chatter for specific topics or people.

Tweets of gold

Savvy businesses see gold in the information: Consumers are talking about them on Twitter, and they get to respond more quickly than ever.

“In the past, companies would hire a market research firm to understand their audience,” says Mike Hudack, CEO of Blip.tv, a New York-based video website.

“Now we use Twitter to get the fastest, most honest research any company ever heard — the good, bad and ugly — and it doesn’t cost a cent,” he says.

With Twitter, Hudack can monitor every mention of Blip.tv and see exactly what people are saying. He can drop notes about things the company is thinking of doing and get instant feedback about whether they’re worth pursuing.

It is hard to find projections for the blossoming market, Martin and others say. Martin estimates hundreds of companies worldwide — including Saturn and Smart Car, for example — use internal social networks, compared with a fraction of that a year ago.

“The spread of the workforce has put a premium on tech tools that let people collaborate, learn and share info from different parts of the world,” says Ross Mayfield, co-founder of business-software maker Socialtext. He cites studies that show 85% of all employees work on projects with colleagues in other offices.

The employee-only sites are an excellent format for large, geographically dispersed organizations to communicate internally and elicit ideas from workers, says Tom Beauchamp, chief information officer at Hot Topic, a retail chain of 690 stores for teens in all 50 states.

The chain is testing an internal site, powered by software from vendor Socialcast, that will let about 6,000 employees share data and create ideas when it launches later this year.

Cutting in-box clutter

Practically, corporate social networks also cut down on unnecessary e-mail and instant messages among co-workers, says Dan Nye, CEO of LinkedIn, a social network of more than 28 million people, most of them business professionals. Private social networks let “people choose what they want to read and discuss, based on their participation, without being intrusive and annoying,” he says.

LinkedIn’s new service, Company Groups, digitally gathers into a single, private Web forum all of a company’s employees. There, they can talk to one another, share ideas and ask company-related questions. So far, 1,000 companies have signed up for the service.