It is not some group of people attempting to establish a custom. The custom was established in the very early days of Internet (you know, Internet and email existed long time before term "the web" was invented). Basically, that "group of people" is just trying to defend something good.
The custom seems to have been redefined in recent years to the simplified form you mention. As I remember the custom it was that inline replies should be under the text they are in response to. Usually these inline replies are best. Replies to the entire message or changing the direction of the thread should be top posted. In general large chunks of disconnected text should not be bottom posted as they require you to scroll through crap you've already read. Better yet do it right and do inline responses. :)
Interesting statistical note: Most people that ask questions are top-posters. Most people who give good answers are bottom-posters. Tells something ;-)
Is that like "97% of statistics are made up on the spot."? Or "97% of people who participate in a list etiquette discussion have boring jobs."?
-- Michael <mogmios@xxxxxxxxxxxxxxxxx> http://kavlon.org