If I allow people to edit a wiki, how will I know it's good quality?To me this is one of the more overstated risks. Yes, someone could post something wrong on the wiki, but they likely are already putting that same information in emails and IMs. At least on the wiki you can get correction. If you are really concerned, you can moderate. The reality is that in most cases it's safer to make things fairly public than to allow them to be hidden until the subpoena. Plus you can rely on human nature ...
Consider what recently happened when Training Zone published a laughable article - The elearning diet: Not recommended for long term results. I understand why they did it. Controversy gets views and links. Look at the number of views as compared to other articles on the site. It worked. This article is getting lots of page views. Except that whatever belief we might have had in any kind of editorial quality just evaporated. Unsubscribe and subscribe instead to any quality blogger such as Clive (read his response: E-learning: the fad that's lasted 30 years). Where's the quality? The publication? Or the blogger? Sheesh.
But back to the response that the article got - lots of views and comments. Their most popular by far. Why?
People (especially employees) enjoy the opportunity to find things that are wrong, tell you why its are wrong, and maybe correct them.This natural instinct is the best solution to poor quality content.