I mostly use the source editor over the visual editor, but use the latter for referencing and I use ProveIt for citations, as I'm not too good at using the templates. I joined Wikipedia to try and improve the article Gulval. I am currently creating an article on Dingle Farm Tearoom, although I am on-and-off with this.
The encyclopedia proper is the main namespace and contains all of Wikipedia's encyclopedia articles. All of the other namespaces have prefixes, which must be included (followed by a colon) at the beginning of links to pages in those namespaces in order for those links to work. Otherwise, the links will point to the main namespace, which has no prefix.
Currently, Wikipedia has 30 namespaces: 14 subject namespaces, 14 corresponding talk namespaces, and 2 virtual namespaces.