Drupal has a good potential to be used as a blog, forum (some what), wiki or any other dedicated web application or combination of two or more services. Drupal as a wiki, out of the box is a little weird. Problem is Drupal organizes wiki as book pages and books and book pages are related. Some people might not agree that book node/content type is a form of wiki but they can be used as one.

Problem:
The problem using Drupal book module and book pages as wiki is, the book page module adds book outline form part and the book outline menu as node/x/outline to all node types. All the node types do not need to be part of a book/wiki page. So this is the awkward part. I had to develop an application that had a wiki as a part with blogs and events as other services. So I faced this problem.