In the context of the broader internet(s) I think you're right -- the best resources do bubble to the top and there is visibility of the runners up too.

However, I'm not so sure that the same applies in the enterprise 2.0 space. In many organisations there just aren't enough people to reach critical mass for the emergent phenomena to work. But, in my experience, there are often enough people to get the duplication.

Regards,
Andrew.