But it wouldn't handle indentation properly, unless you define a standard formatting convention similar to Markdown. For example, you need to handle bullet points. But what if a plain, non-indented text just happens to contain a star at the start of a line? This means headaches for text writers to avoid these edge cases, and wrong indentation when viewing legacy texts.
Also, all viewers would have to support it, which somewhat defeats the purpose of using plain text.
I'm not talking tab characters, I'm talking indentation of whole paragraphs with plain spaces, as seen in the article. Most existing viewers just wrap long lines so that the wrapped content is unindented: this makes any indentation hard to notice and mostly useless. For your proposition to be viable, viewing software has to detect indentation and keep that indentation in wrapped lines.
> Asterisks are fine.
Ok, but usually you want to indent the wrapped contents by 2 columns otherwise asterisks become hard to notice. This is only possible with special magic in the viewer.
--- BEGIN MESSAGE ---
--- BEGIN BLOCK QUOTE ---
--- BEGIN BLOCK QUOTE ---
I'm not talking tab characters, I'm talking indentation of whole paragraphs
with plain spaces, as seen in the article.
--- END BLOCK QUOTE ---
Ah, okay. You're right, indenting an entire paragraph is hard.
--- BEGIN BLOCK QUOTE ---
This is the kind of thing they'd do on Usenet.
--- END BLOCK QUOTE ---
--- END BLOCK QUOTE ---
All you get is a very verbose markup language :-)
--- END MESSAGE ---
This is the best solution, because you never know how large the text will be when rendered by the user's software. For example, this is how it rendered on my iPad:
