We're using module/sub-module/article/en as the URL. The folder structures DO have very deep folder relationships. But in other wiki systems like redmine wiki, github wiki, they have all wiki pages in the root folder. In this way:
- Different wiki pages can link to other pages easily
- There will be no conflicts at the names of wiki pages
- Title of wiki pages has a relationship with wiki pages' name. e.g., when users create a title `How to Debug Lua`, then the wiki page's file name will be `how-to-debug-lua`.

So comparing to other wiki systems, there're 2 problems existing in our current documents system has some pros and cons:

**Pros**
- Better permission control via github repository. It's easier than redmine wiki and github wiki to **review** and **merge** docs contributions. Traditional wiki systems have no concept of review and merge.
- Easy to analyse contributors, activities via [github graph](https://github.com/cocos2d/cocos-docs/graphs/contributors)
- Easy to use offline markdown editors

**Cons**
- 1. If we refactor the folder structure in the future, then all google search results to our docs system will be invalid
- 2. Impossible to link other wiki pages via a simple `[[wiki page name]]`, because they're in different folders.

I don't know how to resolve this, just post the problems here.