https://en.wikipedia.org/wiki/Posting_style
維基百科 post sytle
When a message is replied to in e-mail, Internet forums, or Usenet, the original can often be included, or “quoted”, in a variety of different posting styles.
在email，internet 論壇或者usenet回覆信息時，原始的郵件經常被通過各種郵件格式引用。
The main options are interleaved posting (also called inline replying, in which the different parts of the reply follow the relevant parts of the original post), bottom-posting (in which the reply follows the quote) or top-posting (in which the reply precedes the quoted original message). For each of those options, there is also the issue of whether trimming of the original text is allowed, required, or preferred.
主要的選擇有
interleaved posting或者叫inline reply：緊跟原始郵件的相關部分回覆不通的部分。
bottom post：在引用之後回覆。
top post：在引入原始郵件之前回復
對應這些選擇，是否允許、需要或者說優先修改原始的文件，這是一個問題。
For a long time the traditional style was to post the answer below as much of the quoted original as was necessary to understand the reply (bottom or inline). Many years later, when email became widespread in business communication, it became a widespread practice to reply above the entire original and leave it (supposedly untouched) below the reply.
很長一段時間，在引用原始文件之後回覆郵件這種傳統方式（bottom或者inline）被認爲有利於理解。多年之後，隨着email成爲商業交流的主流，在全部原始郵件之上回復，把原始未改變的郵件反正回覆之後成爲了慣例。
While each online community differs on which styles are appropriate or acceptable, within some communities the use of the “wrong” method risks being seen as a breach of netiquette, and can provoke vehement response from community regulars.
然而每個在線社團的風格都不一樣，一些社區使用錯誤方式可能被認爲有失網絡禮儀，並且可能引起社團大部分人的強烈不滿。
Quoting previous messages
In an e-mail reply, it is sometimes appropriate to include a full or partial copy of the original message that is being replied to. As opposed to in-person conversations and Internet chats, email responses may be received long after the original message was sent, so the original sender may have forgotten, misplaced or deleted the original. Many email reading programs (mail user agents) encourage this behaviour by automatically including a copy of the original message in the reply editing window.
回覆email時，包含全部或者部分需要回復的原始信息是一種合適的做法。相對於個人交談或者網絡聊天，郵件是比較慢的，可能原始郵件已經發出很久了，才收到了回覆郵件，原始郵件的發送人可能已經忘了或者刪除了原始郵件。大部分郵件程序在回覆編輯窗口會自動包含原始郵件的備份信息。
Quoted text from previous messages is usually distinguished in some way from the new (reply) text. At a minimum, the two parts are given different indentation. In the example below, the first line is the original message, the second line is the reply:
引用之前信息通常會和當前的回覆區分開來。至少兩部分會使用不同的縮進。就像下面的例子，第一行是原始信息，第二行是回覆。
Alternatively, special delimiter lines may be used:
或者，使用特殊的分隔符
For extra clarity, blank lines may also be inserted between the two parts. When using an email medium that supports text markup (such as HTML or RTF), the previous text may be indicated by a distinctive font and/or color:
爲了更清晰，在兩部分之間會插入空行。如果使用了email支持text makrup（如果HTML貨RTF），之前的文字會使用特殊字體或者顏色
Quoted line prefix
未完待續