You will find two kinds of links in the text of wiki pages. Internal links go between wiki pages. External links go to other places on the internet.
Internal Links
An internal link will look at many sites to find page named by an internal link.
Hover over an internal link to see what domains it will poll and in what order.
Hover over a page's flag to see where it is stored. Notice colored boarders indicating various sources.
An internal link might find that you've edited a page and have that page in your browser local storage. The link will show you that page instead of any other.
Hover over the page's flag to learn were it was found. Border colors are added to pages as follows: yellow for local storage, blue for remote sites, and, green for plugin documentation.
Internal links are always the title of the page they reference. This sometimes leads to awkward grammar but has the advantage of presenting meaningful names.
External Links
An external link is like most other links on the web. When you click the link you go to the referenced site and start browsing there. wikipedia 
External links open the referenced page in a new browser tab so that wiki pages are left undisturbed.
Convention has external links written as a single link word at the end of a paragraph. Link words like site, post, pdf and video make it clear what you will get. Well known sites like bbc and wikipedia make good link words too.
You can click to Find The Beginning of a site.
You can click to Read History of a page.