Any ideas for business model for distributed Free knowledgebase?

I am now reading the interesting article at http://www.virtualschool.edu/mon/SoftwareEngineering/BrooksNoSilverBullet.html, referred to by http://en.wikipedia.org/wiki/List_of_important_publications_in_computer_science, which is in turn referred to by http://www.livejournal.com/users/mulix/141984.html?nc=2&style=mine.

As I was reading the section about expert systems and knowledge bases needed by expert systems, the following question came to my mind:
Suppose we want to develop, build and deploy an Internet based database of rules for software test cases generation.
We would like to have software test engineers contribute their wisdom to the database, for the benefit of everyone.
We would also like to allow GPL-like freedom to the users of the information in the database.

Thus, access to the database and the expert system will be free for everyone. Everyone will also be able to contribute new knowledge to the system. Everyone will also be able to have a private repository of knowledge about testing those parts of his software, which he wants to keep secret for now.

The big question:
Is there any business model, which can make the above work?
Such a business model would have to:

  1. Encourage users of the system to contribute information to the public rather than keep it to themselves.
  2. Encourage payment to the company which developed and is maintaining the expert system and the database and the network of hosts, which make the data accessible to the public.
  3. Discourage people from defiling the database by filling it with junk information.

Author: Omer Zak

I am deaf since birth. I played with big computers which eat punched cards and spew out printouts since age 12. Ever since they became available, I work and play with desktop size computers which eat keyboard keypresses and spew out display pixels. Among other things, I developed software which helped the deaf in Israel use the telephone network, by means of home computers equipped with modems. Several years later, I developed Hebrew localizations for some cellular phones, which helped the deaf in Israel utilize the cellular phone networks. I am interested in entrepreneurship, Science Fiction and making the world more accessible to people with disabilities.