Thu, 09 Sep 2010
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
Q: What is the most annoying thing on usenet and in e-mail?
It seems that major e-mail clients including Gmail encourage people to top-post and actively sabotage any other mode of operation. Recently I have discovered that with many top-posters the conversation is very inefficient, as top-posters when constructing their reply tend to stop reading after answering the first question in the original mail.
It is really hard to keep them focused on the whole mail, because for answering all the questions presented to them, they would have to scroll down and back again.