Added example Google FTP crawler-block (commented-out).

text/email.can

 ; Enter disallowed (source or destination) e-mail addresses in this file
 ; Wildcard characters (*, ^, ~) are allowed and ! negates the match
-; Rejection message file: text/bademail.msg
\ No newline at end of file
+; Rejection message file: text/bademail.msg
+
+; Prevent Google's FTP-crawler by uncommenting the following line:
+; googlebot@google.com