Jamal,

Regarding top-posting being more convenient for the blind:
suitable-trimmed bottom-posting is just too entrenched and useful for
sighted readers -- and so very probably won't be going away. What
makes it even nicer for sighted readers is that, with good software,
the quoted text is usually colored depending on how many quoting
symbols (usually a greater-than and a space). This makes it extemely
easy for sighted readers to quickly scan over parts they've seen
before.

I think the long-term solution is:

1. When providing quoted context in a reply, bottom-posting.

2. Posters need to suitably trim out all un-needed text.

3. All lines containing quoted material should start with one or more
pairs of a greater-than symbol and space.

4. Screen reader software for the blind should get the functionality
of easily and somewhat intelligently being able to jump down
paragraph-at-a-time through quoted text. Seems to me that would be a
great "killer-app feature" for mail-/news-readers for the blind.

For those to work though, it will take everyone to gently but
diligently remind others to please follow those conventions.

When it doubt of how to format your email text, I'd suggest falling
back on [Markdown][1] syntax (since it was designed to basically mimic
what you usually see in plain-text emails anyway). Maybe screen-reader
software of the future could actually understand Markdown (for
example, speaking *this* louder that other text).

[1]: http://daringfireball.net/projects/markdown/

---John