Users of other wikis, such as Wikipedia, may have noticed that namespaces are much more widely used on UESP.
Unlike other wikis (which put most pages in the "Main" namespace), on UESP everything is categorized. All articles related to the game Skyrim are in the [[Skyrim:]] namespace, for example. This helps to organize the content of the site, in particular in cases where pages with the same name are needed for each separate game. Therefore, instead of having a single page named [[Breton]] that has to provide information on Bretons relevant to every TES game, there are multiple pages (Morrowind:Breton, Oblivion:Breton, etc.), each describing game-specific information, and also a Lore:Breton page which describes general (non-game-specific) information. Furthermore, searching is customized to take advantage of namespaces.
A complete list of UESPWiki namespaces is available at UESPWiki:Namespaces.
When you create links to pages in a namespace you have to add the namespace to the link yourself. There are additional shortcuts you can use. The way to use these is to choose the appropriate two-letter abbreviation, AR, DF, BS, RG, MW, TR, BM, OB, SI, or SR and format the link like so:
This will automatically create a link to Oblivion:Breton from anywhere on the site. To create a link with a different display text, simply provide an additional parameter:
This will create a link to Oblivion:Breton which displays as Breton.
Finally, if you want to have a display name that is the same as the name of the article, you can format it like this:
This will add "Breton" as display name, so the link will display as Breton (without the namespace). When you edit the page again, you will see the wiki software has automatically changed the link to:
Generally speaking, all links within a given namespace should if possible link to other pages within that namespace. Thus, in an Oblivion article about a character who is a Breton, it would not be correct to link to the Lore:Breton page. Rather, the link should point to the Oblivion:Breton page. Exceptions are made for subjects which cover multiple games, such as general lore subjects which are found in the Lore namespace. Also, there may be times when an article about something in one game will reference a related article in another, such as Oblivion:M'aiq the Liar, which is about a character who also appeared in Morrowind. But by default, you should always keep links within the same namespace as the page they are on.
When creating a page, be sure to create it in the correct namespace. In particular, pages created in the main namespace will in general be immediately deleted (see the Deletion Policy). If you follow a link to a non-existent page, or for any other reason are about to create a new page, first check that the page does not already exist somewhere else on the site.