When asking a question, the "How to Format" information says:
► _italic_ or **bold**
suggesting using underscores to italicize a word.
Yet if one selects a word and clicks on the "I" in the editing menu, the result is:
using asterisks instead of underscores.
Is one method preferred over the other, and why are the "How to" and the "I" different?
Laurel points out that it's even more complicated than simply have two different ways of indicating the same thing.
b**ol**d produces "bold", as expected, while
b__ol__d produces "b__ol__d", with the embedded underscores having no special meaning.
Since the two characters have different effects, it is even more confusing than I had originally thought for the button and the How-to to not use the same character.
I'd suggest that the asterisk should be the officially preferred character in all documentation and examples, with the underscore mentioned as also being allowed, with a warning that it doesn't work in some circumstances.