A signature delimiter is a line of text in an email or a news posting that separates the body of a message from the sender's signature. The commonly accepted delimiter is:
-- 

(that's two dashes, a space, and a newline - "-- \n")

Generally, one should not quote anything after the last signature delimiter when replying. Some mail and news programs automatically do this; with others the user should (but usually doesn't) snip the signature manually.

In certain newsgroups you will get flamed for quoting a signature or using an incorrect delimiter.
Those who quote my signature and have modems of questionable quality find their connections dropped... +++ATH0 is my friend