What is a wiki?
TL;DR
Wikis are community maintained knowledge base articles, enabled by a workflow of discussing, implementing and tracking revisions with meaningful comments, when needed.
Discussing changes
When to start a discussion?
When there are questions about recent #wiki changes or someone simply would like to discuss a change before adding it, then please start the discussion below the wiki article. However, because the content of the wiki is the central focal point, the replies in the wiki thread are automatically deleted, e.g. after 14 days.
Why auto-delete topic replies?
Auto-deletion of topic replies are done to bump wiki articles to the top of the latest topics when a change is added. If replies are not automatically deleted, then the timestamp of the last reply in the thread determines where the topic will be sorted, which is chronologically. If e.g. the auto-deletion is set to 14 days, then a wiki article will be utmost not bump to the top for 14 days if there are no further replies, but there are wiki changes. This is considered an acceptable trade-off. Because we do want to allow discussions, but we also want to maintain the focus on the wiki article.
Implementing and tracking changes
To change a wiki, click on the Edit Wiki button in the upper right corner: 
Make your changes as small as possible. This makes tracking changes easier. Also don’t forget to leave a revision comment, if needed. This can be done in the field that says why are you editing?, which will appear when you click on the 
logo in the upper left corner, next to your username: 