Posting Guidelines

[Brian Howell]

 When responding to a post, please do not include the previous post's text as a block either before or after the post. In other words, no top or bottom posting, please. The threaded nature of Google Groups and most email readers makes it easy to refer back to the discussion's previous posts to establish context. This will also make your comment stand out more.

Note that this does not preclude interleaved posting (also called point-by-point), in which portions of the previous message are cited and responded to specifically. Trimming the previous message to isolate key points is also acceptable, in which case the trimmed portion should be placed before your response. (This is in effect a degenerate case of point-by-point.)

There is also an exception for when the subject line is changed, as that will create a new thread. In such cases, you may retain the previous post at the bottom of your response to provide context (in other words, top post).

More here: https://en.wikipedia.org/wiki/Posting_style