DM News: Are Challenge-Response Systems a Challenge to E-Mail Marketers?

DM News reviews the slow penetration of challenge-response anti-spam measures that also stymie many email marketing campaigns and prevent many newsletter subscriptions from getting delivered. Slow pickup rates for the often free services may show that the hassle of forcing email senders to jump through hoops to make sure their email gets delivered might be just a shade too much to guarantee that users will get all of their important email.