Some companies see social medias as bad thing that distracts the employees and lowers the working efficiency. But I think there might be some opportunities to improve flow of information within the company. Social medias could be customized to company's needs, for example block some features and make some of your own.

I think in many workplaces there would be benefits if employees could "brainstorm" in real-time chat rooms or lounges. E-mail and personal meetings are widely used for that but why not move some of that to social network?

Also work-related questions for employees closest manager could be sent when they come to mind, and if the manager was busy at some other activity he/she could answer those questions when they get back to their desk. Manager could then assess the situation and decide wheter to answer the question or get the answers from higher up. If managers had their own "chat room" where employees could send the questions (but could not read other peoples questions so that it would feel easier to ask knowing that only superiors can read them), any available other manager could answer the question right away. There would have to be some guidelines for managers what kind of questions can be answered on behalf of other managers. Stepping on someone elses toes isn't much improvement to general atmosphere.

Twitter-like newsfeed application could publish any important updates instantly. If someone was waiting for other peoples work to finish, that would cut the waiting times to minimum. Those newsfeeds could be customized so that those directly related to one's own work could be shown as some kind of pop-up messages. Maybe the working motivation would rise if employees would know that anyone can check if you have finished anything today. And managers would be able to transfer employees to other tasks if they have finished their own tasks earlier.

 If such things could be implemented without employees getting the feeling of "big brother" wathcing over their shoulder I think there could be many good uses for social media at workplaces.