recipient_delimiter

[privacy.at Anonymous Remailer]

What does the following mean exactly - How do I know if "my MTA 
supports it"?

What exactly do I have to set up on my MTA? Do I tell my MTA to 
alias all mail for echolot+* to echolot(*)? Do I have multiple 
mailboxes all starting echolot+? Or what exactly? I'm running 
Exim4 under Debian (Sarge).

(*) If this option, do I have to run procmail?

(from man pingd.conf)

       SYSTEM SPECIFIC OPTIONS

       recipient_delimiter
           The recipient_delimiter parameter specifies the 
separator between
           user names and address extensions (user+foo).

           If it is an empty string Echolot does not make use of 
user defined
           mailboxes but rather encodes the message type etc in 
a Com-
           ment/Realname part of an address.

           The use of recipient_delimiter is strongly 
recommended if your MTA
           setup supports it.

                   Default: 'recipient_delimiter' => '+',
                   Example: 'recipient_delimiter' => '-',
                            'recipient_delimiter' => '',