Top-posting, also known as Jeopardy-style because it places the "answer" before the "question", is probably just another one of those Microsoftian evils. For decades quotation was done one way, a logical way... then along come Microsoft and that sort, gotta do it differently, and stupidly if at all possible. Almost as annoying as top-posting are the newbies who come along and criticize the rest of us for following the logical standard. Must be the current fashion... At least people don't feel the need so much to point out spelling errors as was their wont in earlier days.
RFC 1855 : Netiquette Guidelines says...Thus, the proper way to quote is like so...
Somebody wrote...
> Blah blah blahblah blahblah blah blahblahblahblah
> blah blahblah blah blah blah blah blah blah blah blah blah
> blah blahblahblah.
I reply blahblah blah blah blah blah blah blah blah blah
blahblahblah blahblah blah blah blahblah blahblahblah blah
blah blah.
> Blah blahblah blahblahblah blah blah blah blah blah blah
> blah blahblah.
Maybe so, but blahblah blahblah blah blah blah blah blah blah
blahblah blahblah blah blah blahblah blah blahblah blah
blah!
When quoting more than one person, you can use initials or something for attribution...
Somebody wrote...
S> Blah blah blahblah blahblah blah blahblahblahblah
S> blah blahblah blah blah blah blah blah blah.
I reply blahblah blah blah blah blah blah blah blah blah
blahblahblah blahblah blah blah blahblah blahblahblah blah
blah blah.
Another Person agreed...
AP> Blah blah blah blah blahblah blahblah blahblahblahblah
AP> blah blahblah blahblah blah.
To which I say blahblah blahblah blah blah blahblah!
S> Blah blahblah blah blahblahblahblah
Blahblahblahblahblahblahblahblahblahblah!
When quoting authority, reference material or such, one uses #, like the unix root prompt...
The Jargon File says...
# Blah blah blahblah blahblah blah blah blah blahblah
# blah blahblah blah blah blah blah blah blah blah blah blah
# blah blahblahblah.
There is one (yes I admit it, one (but only one)) advantage that I can see to Jeopardy-style, and that is that, particularly in a Windowy environment, the new text appears right there in the window when the message is opened. Disadvantages however are many, and fairly obvious to anyone who thinks about it for a bit. Several are noted on Why Bottom-posting is better than Top-posting.
As one fellow put it, the standard is what it is because...
>top
>to
>bottom
>from
>read
>to
>difficult
>it
>find
>People