It's asked that editors avoid using HTML, because the wiki uses MediaWiki code. The HTML explained here does not have an equivalent in MediaWiki.
Used to make a new line.
- 1 2 3<br/>4 5 6 = (see below)
- 1 2 3
4 5 6
The font code has multiple functions, but in all cases, the tag must be closed with </span>.
- <span style="font-color:blue">This text is blue</span> = This text is blue
Font size is relative, centered at 1 em.
- <span style="font-size:1.25em">This text is 1.25x as large as usual.</span> = This text is 1.25x as large as usual.
Used for leaving important comments to editors. For obvious reasons, misuse will lead to warnings and/or temporary blocking. The Sysops will be aware...
- <!--This text becomes invisible--> = (you have to click the edit-link to actually see the result)
Not really used on articles, but people may find use for it when making to-do lists on there userpages and they want to "cross something off."
- <del></font>Strikethrough</del></span> =