A snippet taken from http://www.netmeister.org/news/learn2quote2.html ....
Why should I place my response below the quoted text?
Usually, the reading-flow is from left to right and from top to bottom, and people expect a chronological sequence similar to this. Especially people who are reading a lot of articles (and who therefore would qualify as the ideal person to answer your question) appreciate it if they can read at first the text to which you are referring. The quoted text is some kind of help to remember the topic, which of course will not work, if you place the quoted text below your response.
Furthermore, that's the standard. This may sound as a weak argument, but since people are not used to reading the other way around, they have no idea what you are referring to and have to go back and forth between the referenced articles, have to jump between different articles and so on. In short - reading the article becomes more and more difficult - for people who read many articles it is reason enough to skip the entire article, if the context is not obvious.
And besides: doesn't it look stupid to first get the answer and then see the question? (Aside from Jeopardy, of course.)
Furthermore, you (yes: You) save a lot of time using this way of quoting: You do not need to repeat what the person you refer to wrote, in order to show the context. You just place your comment after the text you wish to comment upon, and everybody immediately knows what you refer to. Also, you realize which text you are *not* responding to and can delete these parts.
So: using this technique you save time, your readers don't have to waste time, you save bandwidth and disk-space. Isn't it great what you can achieve by such simple means?
... When including text from a previous message in the thread, trim it down to include only text pertinent to your response. Your response should appear below the quoted information. ... In follow-ups, whether News or Mail, CUT headers & signatures, PRUNE quotations, and preserve order. That is to say, quote above each part of your reply as much of the earlier stuff as is needed to put the new material in context, but no more; most readers will be able
to refer to the earlier article itself, if need be. Never write on the same line as a quotation, except in lists and notes; generally leave a wholly blank line between. Do not quote the header or the signature, unless it is relevant to do so. ...(/quote) See http://www.jsiinc.com/newsgroup_document.htm
(quote) If you are sending a reply to a message or a posting be sure you summarize the original at the top of the message, or include just enough text of the original to give a context. This will make sure readers understand when they start to read your response. Since NetNews, especially, is proliferated by distributing the postings from one host to another, it is possible to see a response to a message before seeing the original. Giving context helps everyone. But do not include the entire original! (/quote)http://www.cis.ohio-state.edu/cgi-bin/rfc/rfc1855.html
The object is to communicate with the reader, not just make life easy for the writer. It's the ame idea behind using mark-up and formatting and layout and design to build a web site -- the author does a little work and sufffers a little invonvenince so all the readers can benefit. If you've got something worthwhile to say, it's worth putting some thought into designing the message.
With posts containing multiple points and questions, a topposted answer is normally ambigious.
Discussions normally involve refuting, commenting on, agreeing with points a previous poster has made, so a question followed by an answer is a normal top-down thing. Topposting is normally considered as jeopardy posting, since here the answer would come before the question
People don't all use Usenet in the same way.
You are assuming here that all Usenet posts are available in your news reader, so you can see all the posts - this assumption does not hold water, since Usenet is a finite resource.
Usenet works by sending a copy of all new posts to each and every server in a peer to peer network. So every news server may have a copy of your post - except those that decide they don't want your posts.
So every server has limited disk space, once that limit has been reached, posts get dropped. With binaries groups taking up a huge portion of space, there's not much room left for text only posts.
Also because of limited disk space, posts expire and are removed. So in a long-running thread, some newsservers won't have a significant portion of threads because they've expired.
There's also network problems that cause posts to be dropped, plus filters.
Bottom posting involves quoting only the content that is relevant to what's being quoted or referred to, so a good poster will trim out all the bits he's not directly commenting on. Where he's commenting on a large body of text, he would normally summarise the main point, and then add his comment to that.
You should see the beginnings of a bottom posters reply when you are at the top of a post. As is the case with this reply of mine.
So that would limit the number of posts a Usenet server could hold, plus you'd not be putting your point across as well as you could. Why include the post at all if you are not commenting on anything within it? Might as well just not quote anything at all, and save the wasted bandwidth!
Bottom posting, with good quoting is more efficient resource wise, plus its easier to get involved in a thread that is correctly bottom posted, even if you are missing a large chunk of that thread.
There are some good links covering this topic, here's a starting point for you: http://www.html-faq.com/faq.php?key=topposting
Its all really about maximising your ability to communicate. Some people go on about how they don't care about how they communicate, which is really strange considering they are participating in a highly communicative environment on Usenet.