Can the stuff employees do on their home computers end up getting you dragged into court? That’s what’s happening to one company now.

Richard Frenkel, an employee at tech company Cisco, writes an anonymous personal blog in which he mostly criticizes patent lawyers. Apparently, he may have stepped over the line and written some defamatory comments about two lawyers in particular.

So they found out who wrote the blog and now they’re suing Frenkel – and his employer. Cisco’s saying that the blog was personal and had no affiliation with the company. But the company’s being included in the suit because, allegedly, Frenkel’s boss knew about the blog and the content he was posting.

In response, Cisco updated its blogging policy, now requiring employees who write blogs to identify themselves as Cisco employees when their content is related to the company’s business. And they must include a disclaimer differentiating between their views and the views of the company.

As this suit shows, a blogging policy is a good idea if that’s an activity your employees engage in. Besides defamation, other common issues to address in the policy are harassment of co-workers and the leaking of the confidential information.

Obviously, you can’t keep track of everything employees do in their spare time, but the boss in the Cisco case might have been better off saying something to the employee, if he really did know what was going on. Also, a good policy will remind employees that what they say online is public and never really anonymous.

Read more about the suit here.