It doesn't understand any markup language, you can use just plain HTML.
It doesn't have a helper bar, but it recognizes some of the traditional shortcuts for formatting. They are described in an alt text for the page.
The main use cases that I've seen for it are people writing down something quick (therefore not a lot of formatting requirements), or people copy pasting information from another HTML page that they want to keep a reference too (the formatting is kept from original page).
It doesn't have a helper bar, but it recognizes some of the traditional shortcuts for formatting. They are described in an alt text for the page.
The main use cases that I've seen for it are people writing down something quick (therefore not a lot of formatting requirements), or people copy pasting information from another HTML page that they want to keep a reference too (the formatting is kept from original page).