Why prohibit social networking in the workplace?

A colleague recently pointed out that some workplaces are prohibiting the use of social networking tools such as twitter and facebook, and made reference to an article entitled Millenials will Route Around IT departments. She asks:

What should we implement, how far should we go to get buy-in from the higher-ups, and what happens if we don't? Are we better off that way?

I completely agree that we should be embracing technology that increases the quantity and improves the quality of communication. Of course, there will always be non-work-related communication, but that doesn't occur because of technology. Take walk around the office to rest your eyes, or even while you're working someone will come up and you'll have a personal conversation. These conversations increase the quality of our relationships and, in turn, the quality of our communication. Besides, how can you understand how someone thinks and works without talking to them? In addition, I hope our bosses hired us because they have faith in our ability to adjust our personal communication when it interferes with work.

In relation to students, I think it is extremely important that we are familiar with what technologies they are currently comfortable with, rather than expecting them to adhere to a "foreign" user interface with a steep learning curve. As an advisor, my students can take my advice, or leave it. Listen to or ignore me. So that forces me to ask myself, "What can I do to earn their respect and trust?" One way is to participate in their social networks. Not only do I begin to understand how they communicate and what technologies they are comfortable with, but I begin to earn their trust. "He is like us! He is on our side!" This is invaluable and immeasurable. Plus it helps me forget that I'll turn 30 soon :o

There is no way I can keep up with technology and trends by myself, so I have to rely on the experts in my social network to keep me informed. If managers and admins feel they can't trust our participation in these social networks then we have to openly question their judgment while making our case with solid evidence. They should recognize our need for flexibility in a tech world that is constantly in flux. If they don't trust our decisions or respect our passion, then why were we hired in the first place?