Wiki is a good idea. The idea is particularly useful in Wikipedia. I love the feature that you can create a link (the definition of a word) using the syntax of [[Shanghai]]. Shanghai will be a hyperlink to http://en.wikipedia.org/wiki/shanghai.
If the term is defined, the link will bring up the page. If the term is not defined, it will bring up the edit page to define it. This is the best idea among all the ideas in Wiki.
If it is applied to [[Blog]], I will like to create sentences like this – to use [[ and ]] to note the names I want to explain in other [[articles]]. Thus I have a good way to describe the [[world I am in]] in a extended way – create the link first and put the description later.