Hey oversensitive legal departments - let's open up social networks at work and get the knowledge transfer/communication/business networking advantages that come with it. 

What's that?  You're afraid they'll say something derogatory?  Sure they will, but didn't they acknowledge all that legal stuff we have in the handbook?  Can't they be held accountable for that at anytime?

Plus, even if you restrict access, don't those policies apply when they talk about your company in unkind terms off the clock?

Sure they do - just ask the NFL's own Philadelphia Eagles, who just fired a worker for slamming the organization on Facebook.  From ESPN:

Dan Leone, who the Inquirer said worked as a west gate chief, was unhappy the team let Brian Dawkins sign with the Denver Broncos in free agency. According to the newspaper, Leone posted the following on his Facebook page: "Dan is [expletive] devastated about Dawkins signing with Denver ... Dam Eagles R Retarted!!"

Despite deleting the comment, Leone told the Inquirer the Eagles fired him by phone days later.

"I shouldn't have put it up there," Leone said, according to the Inquirer. "I was ticked off, and I let my emotions go, but I didn't offend any one person or target a specific individual. I was just upset that we lost such a great guy. Dawkins was one of my favorite players. I made a mistake."

Leone said he was shocked to lose his job of six years.

"I apologized for it," Leone said, according to the paper. "I apologized 20 million times. I never bad-mouthed the organization before. I made one mistake and they terminate me? And they couldn't even bring me into the office to talk to me? They had to do it over the phone? At least look me in the eye. To get done dirty like this, I can't believe it. I'm devastated."

Note to self - calling management "Retarted" may produce varying results.  Note to Facebook - can we get a little spellcheck over here?  Please? 

Open up the network.  They're doing it whether you prevent access or not. Get the benefits...