We've seen newspaper publishers forbid employees from accessing social networks before. The Wall Street Journal is not restricting access, but they are restricting how social networks are used by their employees.

Dow Jones Deputy Managing Editor Alix Freedman sent an email to staff outlining some rules for the use of social media with regards to WSJ and other Dow Jones properties. "The use of social and business networking sites by reporters and editors of the Journal, Newswires and MarketWatch is becoming more commonplace," the email reads. "These ground rules should guide all news employees' actions online, whether on Dow Jones sites or in social-networking, e-mail, personal blogs, or other sites outside Dow Jones."

Some of the ground rules mentioned include:

-  Consult your editor before "connecting" to or "friending" any reporting contacts who may need to be treated as confidential sources. Openly "friending" sources is akin to publicly publishing your Rolodex.

- Let our coverage speak for itself, and don't detail how an article was reported, written or edited.

- Don't discuss articles that haven't been published, meetings you've attended or plan to attend with staff or sources, or interviews that you've conducted.

- Don't disparage the work of colleagues or competitors or aggressively promote your coverage.

And likely the favorite of most critics of these guidelines...

- Business and pleasure should not be mixed on services like Twitter. Common sense should prevail, but if you are in doubt about the appropriateness of a Tweet or posting, discuss it with your editor before sending.

Don't mix business and pleasure. Many proponents of social media that use the medium for work will tell you that's exactly what you are supposed to do.

"The Wall Street Journal's rules for Twitter and the internet rob the paper and its reporters of a few key benefits," says Jeff Jarvis at BuzzMac. "This misses the chance to make their reporting collaborative."

Collaboration, particularly in news, is where social media and blogs thrive. More of the story tends to come out when there is an open conversation.

Editor & Publisher has the entire list of guidelines posted here. Many of them are common sense, and some pertain to things outside of social networking.