Just as a data point (and to initiate my semi-annual 'I'm still here' email), we of course check for and require PTRs for all of our email accreditation customers, many of which are ESPs, and you would be *shocked* (or maybe you wouldn't) how many otherwise relatively clueful and 'wanting to do it right' senders have no clue at all about PTR. Anne Anne P. Mitchell, Esq CEO/President Institute for Social Internet Public Policy http://www.ISIPP.com Member, Cal. Bar Cyberspace Law Committee How do you get to the inbox instead of the spam filter? SuretyMail! How do you protect your inboxes from spam while reducing false positives? SuretyMail! http://www.SuretyMail.com