How much is a tweet worth? And how much does a Twitter follower cost?

In base economic terms, the value of individual Twitter updates seems to be negligible; after all, what is a Twitter post but a few bits of data sent caroming through the Internet? But in a world where social media’s influence can mean the difference between a lucrative sale and another fruitless cold call, social media accounts at companies have taken on added significance.

The question is: Can a company cash in on, and claim ownership of, an employee’s social media account, and if so, what does that mean for workers who are increasingly posting to Twitter, Facebook and Google Plus during work hours?

A lawsuit filed in July could provide some answers.

In October 2010, Noah Kravitz, a writer who lives in Oakland, Calif., quit his job at a popular mobile phone site, Phonedog.com, after nearly four years. The site has two parts — an e-commerce wing, which sells phones, and a blog.

While at the company, Mr. Kravitz, 38, began writing on Twitter under the name Phonedog_Noah, and over time, had amassed 17,000 followers. When he left, he said, PhoneDog told him he could keep his Twitter account in exchange for posting occasionally.