An example of how far the issue is from many employers' minds played out last year when Jim Roberts, a prominent editor at The New York Times, left the paper, taking some 75,000 Twitter followers with him. The paper reportedly had no policy in place to address the issue, and the 26-year-old Times staffer simply changed his handle from @nytjim to @nycjim. The Times apparently opted not to sue. His current follower count: about 82,000.
Some, like Kletter, argue that because Twitter followers are typically real people, who can be seen by anyone clicking on a person's followers link, and who follow and un-follow accounts as they please, the legal basis for claiming ownership of them is questionable.
In cases where a social media account was created as a personal one before the employee joined the company, and then used for both personal and work purposes, it's likely even harder for an employer to claim ownership, Kletter said.
Determining what makes an account personal versus professional is tricky in an age of near-constant social networking, said Archie of Latham & Watkins.
"People's professional work often bleeds over into their personal time thanks to the interconnectedness of mobile devices, and that's only one way ownership disputes can arise," Archie said.
Facebook and LinkedIn each said via email that their official stance is that users own their accounts. Twitter's terms of service say its users own all the content they post to its site.
Because the dividing line between personal and professional is so blurry and varies with the job, the best way for employers to avoid legal disputes is to craft clear policies about how employees should use social media, and what happens to an account when an employee leaves the company.
The policy should at the very least make clear whether the company or the employee will own job-related social media accounts, said John Delaney, a partner with the law firm Morrison & Foerster.
"In journalism, for instance, sometimes the journalist might have a larger following than the newspaper or magazine itself, so spelling out a policy up front could even be a topic of negotiation," said Delaney, who heads Morrison & Foerster's social media practice group.
If a company wants to claim ownership of a social media account, ideally it will keep the employee's name out of the account name, and instead reference the company's name or its brands, he said. And if a company owns an account, it should be used exclusively for business, and not for employees' personal use as well.
"If a company is going to encourage its employees to use their own personal social media accounts for work-related posts and tweets, the company should not expect to obtain ownership over such accounts as a result," Delaney said.
Even when the account is personally owned, there are still legal gray areas when it is used, even if only in part, for that person's work or business.
"Even though the existing practice of the overwhelming majority of employers recognizes employee privacy rights with respect to private, password-protected social media accounts, we recommend that employers undertake a careful review of their social media policies and practices," said Latham & Watkins attorneys Linda Inscoe and Joseph Farrell.
Consider a case in which an employee starts a personal blog related to work, develops a long list of email subscribers and later leaves the company, said Latham & Watkins' Archie.
"Is that list intellectual property? If so, who gets it?" Archie said. After all, going back to the New York Times example, "seventy-five thousand followers on Twitter starts to be worth a little bit of money."