Golden rule of emphasis
"If everything is emphasized, nothing is emphasized"
Generally, the italic font version is used to emphasize a portion of the text, and the bold (strong) font version is used to strongly emphasize said text (more emphasized than italic version).
In this wiki, I use the default font of wiki.js, which is Roboto (sans-serif). In sans-serif fonts the italicized text does not stand out significantly, so I will mostly use the bold (strong) font version for emphasis.
Italic version will instead be used in certain comments and quotes to reflect an opinion, as to refer that text was not originally created by the author or that the meaning can be debatable. This rule however is not strict - if a particular text feels better italicized, I will use that instead, and I also often do some copying and will probably not correct all the inconsistencies.
(source: NICE guide)
Footnotes should not be used in online content. On printed format, like books, they are positioned on the bottom of the page, which is still in the user's field of view. When published in online content, they can end up very far away from the content they're referring to. Readers need to sometimes scroll a long way up and down or risk missing this information. If the information is important, it should be explained in the text or described in a separate page and linked via a hyperlink. If the information is not important, it should not be included at all.
Modern wikis allow bidirectional footnotes, which allow user to get to the footnote in one click and get back to the initial reference in another. More research is needed to know if this feature makes them worth using, or if switching the complete user view (from text down to footnote and then back up) is detremental to user's focus and not worth it.
Hyperlinks should be used to define or explain terms, for cross references in a document, and for links to external documents. They should be used in preference to footnotes, including for references and citations. Enough information should be included in the link for users to understand what it is and where it goes. The links should make sense out of context, because in cases the link itself cannot work - for example in printed versions. If the link takes the reader out of the internal system, the name of the target system / organization should be reflected in the link.