Companies like Symantec Corp. use Chatter, an internal workplace social network.
What would Facebook look like without photos of drunken nights out and tales of misbehaving cats? It might look a lot like the internal social network at the offices of Nikon Instruments Inc.
The tone is decidedly businesslike, as employees exchange messages about customer orders, new products, and closing deals.
And the general rule is that "if you don't want your company president to see it, don't post it," said John Bivona, a customer relations manager at Nikon Instruments, which makes microscopes.
As social networks increasingly dominate communications in private lives, businesses of all sizes -- from tiny start-ups to midsize companies such as Nikon to behemoths such as Dell Inc. -- are adopting them for the workplace.
Although it is difficult to quantify how many companies use internal social networks, a number of corporate software companies have sensed the opportunity and offer various systems, some free to existing customers, others that charge a fee per user.
It's one more instance of how consumer technology trends, such as use of tablet computers, are crossing into office life. Because of Facebook, most people are comfortable with the idea of "following" their colleagues.
But in the business world, the connections are between colleagues, not personal friends or family, and the communications are meant to be about work matters such as team projects, production flaws, and other routine business issues.
At Nikon, for example, which has about 500 employees in offices throughout the United States, Canada, and Brazil, a code of conduct for using the service leaves little room for the idle chit-chat that is pervasive on Facebook.
Still, it can be tricky to transport the mores and practices of social networking into the office.
For instance, some workers prefer to be "lurkers" who read posts rather than write them. Others are just not interested.
At Symantec Corp., a computer security company, a few employees initially disliked the idea of an internal social network but nevertheless used it to air their complaints.
Another issue is how to protect corporate secrets. Generally, the systems are set up so that companies can determine who sees particular files and who belongs to specific groups on the network.
Yet some problems still arise over where the information is ultimately stored. Some social network providers use their own servers. But that may conflict with the rules of some potential clients that prohibit storing company information outside their firewall, said Susan Landry, an analyst with technology research firm Gartner Inc.
Companies that provide social networks respond to the concerns by emphasizing their rigorous security. Still, some offer networks that allow customers to keep their data on their own servers.
And employees may post private information more widely than they should.
"It's sometimes a disaster," Ms. Landry said. "It sometimes gets shut down by security or compliance."
At the same time, even though companies make clear in etiquette guides how to use the networks, missteps occur.
For example, at Symantec, a worker posted his cat's photo in his profile instead of his own. A well-meaning worker at Nikon alerted everyone to apple pie in the kitchen; never mind that colleagues in other offices were not interested.
One of the biggest providers of corporate social networks is Salesforce.com, an online business software company based in San Francisco. It said 80,000 companies use its corporate social network, Chatter, up from around 10,000 when it was introduced a year ago.
Yammer, a start-up and also based in San Francisco, said its service is used by more than 100,000 companies, up from around 80,000 a year ago.
Salesforce and Yammer both offer free versions of their social networks to companies.
Salesforce charges $15 per user a month for its premium network -- existing software customers pay nothing extra, however -- and Yammer's costs $5 per user a month. At Symantec, more than a third of the 18,500 employees are able to use Chatter. More employees, and potentially some of the company's partners, will be added to the network later this summer.
But not everyone who can use a network does so. Chatter's analytic system, which can identify the most influential users, shows that only around 40 percent of the sales team is active on the service, said Tacy Parker, global sales force manager at Symantec.
Keeping posts relevant is important to the success of social networking within companies, managers of the networks agree.
For many employes, one of the benefits of social networks is a decline in email use. Instead of sending out mass mailings, workers post messages or collaborate on presentations within the service.
"Before, we got on conference calls and hoped the information would be passed around," said Scott Lake, director of VIP marketing at Las Vegas-based casino colossus Caesars Entertainment, which uses the Chatter system. "Now, we have a lot fewer calls and meetings."