so... I've been going through all the returned mail.... mostly ip addresses that don't respond to an nslookup.... but this was in the header for one of them

Reporting-MTA: dns; mel-rti21.wanadoo.fr
Received-from-MTA: dns; compuserve.com (61.11.75.128)
Arrival-Date: Thu, 19 Sep 2002 14:49:32 +0200

Final-Recipient: rfc822; [email protected]
Action: Failed
Status: 5.1.1 (bad destination mailbox address)
Remote-MTA: dns; ms18-2.wanadoo.fr
Diagnostic-Code: smtp; 550 RCPT <[email protected]> ERROR. Mailbox
unavailable

So does this mean it's coming from compuserve? or is that just a hop point?