There are many smart business models out there but one I like most is David's actual venture Circle of Experts.

There have been quite some trials to start such a knowledge marketplace. Even Pierre Omidiyar is according to people familiar with the matter still on the lookout for a working model. Circle of Experts has already built up a considerable database of experts all over the world. But the trick is NitronAdvisors pays out up to $250 per consulting hour. This is a major difference to all the lay marketplaces where the incentive for real experts is pretty slim. Such a consulting gig helping in due diligence in a specialized indusrty is pretty interesting offer even for stressed executives.

NitronAdvisors is the company that is selling these expert services and helps companies doing due diligence or specialized research. NitronAdvisors hardly carries much risk as the knowledge requesting client is paying cash before any payments go to the expert. So I rellay like the model...

If you are interested in becoming an an expert you may apply here.