Thoughts about a corporate intranet

Just started to make a concept about the development of intranet site at our company. Since the current site based on a very closed cms system, we have the opportunity to think it over from the foundation.
I have spent plenty of time to read case studies and articles in the topic. I must say, that companies think different about their intranet and the intranet as a tool of communication. The possibilities are usually restricted by data security issues. It is really interesting when you have companies talking about innovation while having strict policies inhouse. How can they be innovative or how much potential do they got when the employees do not have the opportunity or restricted to share their knowledge.
I have found an interesting post about the policy at Google. "All information is shared with everyone." It is common and normal for people are working at small development companies. Employees have the common goals to achieve and they work for the same goal. How can we reach this goal easier? If we do not reinvent the wheel every day. We use the knowledge and experience others gained during their work. It is so easy.
I think strict policies "growing" at companies where there are tensions between departments and employees. The ones got the information can have some advantage over others. The company becomes ineffective. The focus became wider. They will have disadvantage in the competition.
Of course there are markets where there is no real competition (like banking in Hungary). Who will get the last big stakes before the fast growing slows down? I think the companies who will have the focus.
Is it possible that a simple, and from the business point of view, not so important area can effect the success of a company?
Who kows? Maybe..