I’m sure this situation has come up rather a lot:
Social networking added an entirely new morass for employers to navigate.
Should you permit employees to friend one another? (You don’t really have a choice.)
Can you prevent it if they elect to? (Unlikely.)
Can social media policies limit what they say about their workplace on social media sites like Facebook? (Not without potentially infringing employees’ right to discuss working conditions.)
Can you use their social media activity as the basis for firing an employee? (Probably not a good idea.)
My own Facebook policies, to the extent that I can have any policies down here at the bottom of the org chart, are simple: I do not friend anyone I work with, and I turn down requests if I get them.
On the other hand, I have no such rule on Twitter; I figure that none of these folks have time to wade through my tweetstream. I have exactly two followers from the shop, both in my department. And I’m pretty sure I haven’t tweeted anything relevant to work that they haven’t already heard in person, perhaps several times.