Zeilenumbruch in Textmail

[Struppi]

Deshalb wollte ich wissen ob es eine Standardregel für den Zeilenumbruch gibt.

Du meinst http://tools.ietf.org/html/rfc2822
Messages are divided into lines of characters.  A line is a series of
   characters that is delimited with the two characters carriage-return
   and line-feed; that is, the carriage return (CR) character (ASCII
   value 13) followed immediately by the line feed (LF) character (ASCII
   value 10).  (The carriage-return/line-feed pair is usually written in
   this document as "CRLF".)

Struppi.