How would you Wiki?

A few weekends back I went to NYC to visit a few fellow young entrepreneurs. We struck up a conversation about training and internal documentation - two of the most important (and most overlooked) functions of a growing company. One of them (the very successful Anthony Putignano of Xonatek) suggested that the perfect solution was a password-protected internal Wiki. I thought for a second, and then I realized that he was right - it would go a long way in helping to solve both the training and the documentation problem. The collaborative nature of a Wiki is the perfect place for a companies internal documents.

Yesterday I spent the day configuring MediaWiki (recommended to me by Anthony and Dave from Mind Petals) for Pure Adapt. I instantly fell in love with the flexibility and simplicity of the system, and I can envision it being one of our most invaluable assets as we grow.

However, I am running into one MAJOR problem and I can't win the argument in my head, so I figured I'd throw it out there to you. This Wiki will document every important internal process that we have - accounting, hiring, quoting a client, etc. Who exactly should have access to this information? Right now, just the four owners have access. We may grant restricted access to our contracted employees soon. But as we grow we will ultimately hire people to fill the role of accounting and recruiting and what not, and people we hire (contracted or full-time salaried) will need to see that critical information.

Part of me wants to open up all the information to every employee and contractor that we hire (be completely open in our collaborative environment) and part of me really wants to control who sees what to prevent someone from posting our critical passwords on their blog if they become disgruntled. Problem with controlling who sees what is eventually you'll lose control of that - people will share passwords to restricted pages, or employees with permission to view one restricted page will need to access another restricted page, and we'll have a nightmare on our hands. A pissed off employee can screw you regardless of the precautions you take.

The overall Wiki is password protected so only members of Pure Adapt can view the home page, but after that should I password protect certain key documents for owners eyes only? Would that be protecting our best interests or destroying the collaborative nature of the Wiki?