Knowledge management in Social Media

I just finished an article on Building  entrepreneurial knowledge reservoirs (Widding 2005). This article singles out business knowledge is the primary resource that provide competitive advantage. That is if the entrepreneur is using this knowledge to create continuous innovation.  As the article pre-dates the broad mass adaption of social media, it's got me thinking, what's changed?

Business knowledge is what the entrepreneur needs to know to start up a business. This is divided into four categories: product/service, market, organization and financial knowledge. But as an entrepreneur, your not all-knowing, and need to get this knowledge from somewhere. That somewhere is a knowledge reservoir. The article describes three different reservoirs(with some main sources): internal(employees), semi-internal (board) and external(customers). The interaction between the entrepreneur and these reservoirs has changed drastically the last few years:

• the external reservoir is easier to access
• the information in the external reservoir is harder to control and harder to spot
• the external reservoir is more homogeneous (everybody  blabs to everybody)
• the gatekeepers function has changed (controlling information flow between the internal reservoir and the others)

On this last point, I'm unsure about something: is every individual now a gatekeeper as most employees in most companies have the opportunity to publish content in social media? OR is the gatekeeper function ten times more important from a corporate point of view as you want to filter what your employees publish?

In other words; is it common to train all employees, or just an elite spokesgroup to cope with social media?