Comments: Internet-style quoting consists of putting a “>” or other character in front of the original message when you reply or forward it. Recipients can easily distinguish the original message from your comments. This method is preferred on many Internet mailing lists that transmit in plain text only.
Solution: Choose Tools > Options. On the Preferences tab, click Email Options. Under “When replying to a message” and “When forwarding a message”, choose “Prefix each line of the original message”. Set the prefix character(s) under “Prefix each line with”. Click OK twice.