Online social media is changing the way people communicate. It’s also blurring the line between work and play as more employees log on to networking sites like Facebook and Twitter, while they’re both on and off the clock.

These days, employers are finding it increasingly difficult to limit or stop employees from using social media at work because a growing number of companies use the same sites to promote their products and services. And that’s creating some unique legal challenges in areas from privacy to employment, said outside and in-house counsel at a panel discussion Tuesday titled “The Virtual Water Cooler,” held at the 22nd Annual General Counsel Conference in New York.