14th November, 2005
I found this excellent tutorial on how to quote people online. The original article is about usenet (one of the very first internet applications, widely replaced by website foras today) but applies to emails as well. About two thirds of all the mail I get does not honor these rules. Read it here: Learn 2 Quote.
For those too lazy to click on the link, here's a quick summary of the most important rules:
1. Place your response _below_ the text you respond to. This matches the reading direction (top-down) and makes it easy to see what you're responding to.
2. Only quote the necessary part of the mail you're replying to. Leaving out the unimportant makes the mail much easier to read.
3. Text left out when quoting should always be marked with [...]. This indicates to the reader that something has been left out and thus avoids confusion.
Please take this into account the next time you're replying to an email. It will make our online lives so much easier.