1. An email client system for improving efficiency of email discussion for a conversation among a plurality of authors within an email client operating at a user computer having at least a processing device, a user input device and a display, said email client system comprising: an email tag filter for automatically filtering a special tag in email contents, said special tag being inserted at a tag composition component of an email client, extracting original email contents, and identifying tag related information which includes at least an author name corresponding to the extracted original email contents; a content style setting component for automatically receiving the extracted original email contents and tag related information, keeping the tag related information fed by the email tag filter, identifying which part of the extracted original email contents is written by which author according to the tag information, and assigning a style to corresponding extracted original email contents using a user customization style for each author, wherein contents for each of said plurality of authors is assigned a different style; and a display generation component for generating and displaying the email discussion in a single generated email for a conversation among a plurality of authors wherein the email discussion is generated in a single email by organizing extracted original email contents with a different style for each of said plurality of authors.
8. The email system of claim 1 , further comprising two additional user interface components on a user interface of the email client comprising: a discussion mode button for switching between a normal mode and a discussion mode wherein the discussion mode comprises display of the generated email discussion with a different style for each of the plurality of authors; and an author name bar for listing a name of each author who wrote contents in the email, and automatically assigning to each name a special text style and a check box for selecting and deselecting the corresponding author, wherein in an email body on the user interface of the email client, when switching to the discussion mode, texts input by different authors are automatically assigned different text styles respectively according to the text styles assigned to the corresponding author name.