Humane Text Formats
A very interesting blog post from Thomas David Baker comparing Humane Text Formats. These are plain-text alternatives so you don't have to write in HTML. I did a similar comparison, but came to a different conclusion.
I decided to stick with HTML.
I know HTML. If I need to support users that don't know HTML, there are excellent WYSIWYG textarea replacements.
Eventually, you are going to want the full power of HTML. Any markup is either going to be lacking in some way or is going to end up being just as complex.
Everything I write is targeted at the web. I don't need to convert to LaTex or RTF.
Out of the reasons against HTML:
My "needed features" list was similar to his, but I wasn't willing to give up tables. I also needed a pure java implementation and wasn't really willing to do it myself.
The long term viability was the deciding factor. Look at all the alternatives: None of them seems to have a critical mass. Everything supports HTML.
File Formats: (none)