WikiText is a concise, expressive way of typing a wide range of text formatting and hypertext features. Operations like linking become part of the punctuation of your writing.
The key feature of wikitext is the ability to include one tiddler within another (usually referred to as //transclusion//). For example, one could have a tiddler called //Disclaimer// that contains the boilerplate of a legal disclaimer, and then include it within lots of different tiddlers with the macro call `<<tiddler Disclaimer>>`.
One two three four. With a link to HelloThere. And a link to TiddlyWiki and TiddlyWiki5. And a suppressed link to ~HelloThere. And now a [[pretty link|HelloThere]] and another pretty link: [[Introduction]].
This is another macro with content, this time including another macro: <<link to:"HelloThere"><This is a //link// to something in <<version>> of TiddlyWiki.>>. That's that.
<article class="hello" mysignal data-thing='Nothing'><div class="another" mysignal2 data-thing='NothingElse'>This time the text is all squashed up, without line breaks</div></article>