I've always presumed that it was some type of cookie; in the bovious way, to validate the email, but also if you complained to the isp they would be able to know who complained if the isp then showed the complaint to the spammer.
But yeah, trying to fool filters is probably the main purpose. Matt -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
