At the moment many corporations have a negative-cautious view of social media. They frequently block access to facebook, twitter fearing that employees start using such applications uncontrollably or get some malware.
Paradoxically, these same companies encourage people contribute to local internal "social"ized tools like internal wikis, forums, etc. The latter don't work as effectively as expected - partially because people simply don't want to "befriend" with their colleagues, even less with their bosses/subordinates; partially, because there are just too few users and critical mass is never achieved.
The truth is individual companies cannot change the course of development of social media anymore. So why not to change your approach to it? And why not to start with leveraging existing public social media instead re-inventing them internally?
One way is to actually start rewarding people whose usage of social media directly benefits the company. After all, you can hear a lot of interesting ideas or read good articles recommended by your social media friends. To ensure enough attention to work, people can be managed through weekly/monthly targets. However, there is a need for additional rewards if a person creates a good idea for business by synthesizing information available on the Internet and sharing with colleagues.
Another way is to try to learn as much as possible about perspective employees through their social media activity. This should go along with encouraging employees recruit specialists to their departments through their own social networks. Even more so, with the growth of freelancing and outsourcing, increasing number of people will be recruited based on brief virtual interview and portfolio plus social media standing. To do this effectively, companies need to create measurement forms to be able to evaluate persons based on their social media activity.
This inevitably means that companies need to become more open themselves. Information spreads among thousands of users simultaneously these days and keeping trade secrets is increasingly complicated. However, nurturing a community feeling among employees, customers and other stakeholders will help preserve competitive position better.