Wiki extends its twenty year old namesake by providing an unbounded complement of markups of which only a few offer specific syntax for formatting text. The remaining markups configure plugins to show or do work we usually associate with applications.
See Formatting Strengths of various markups.
Just as web pages have grown to become web apps, wiki has grown to be the web application you can edit.
See List of Plugins installed here.
Plugins decide if and how they can be configured by markup. Try double-clicking an item to see if can be edited. Type ctrl/alt-s to exit. Type cmd-i for information while editing. Your edits here will be saved in your browser's local storage.
See Local Changes to discard changes.
Some plugins offer unique editing mechanisms. Clicking check-boxes, Dragging graph nodes, Typing morse code and Marking map locations all affect markup changes that can be viewed, revised or replicated as plain text.
Some plugins get or put internet files. Grep reads other wiki pages, Flagmatic writes new flag icons, Search consults a database, Shell runs server programs and Transport imports other web content.
Some plugins source or sink data. Method and Data share values with other Methods or Radar and Scatter charts, Graphs source data to Transport, Maps and Bikeshare send location data to each other.
See Structures aggregated through page transformations.
See JSON Schema used on disk and over the wire.