Err, doesn't Mailchimp already offer that? http://mailchimp.com/features/inbox-inspector/ http://mailchimp.com/features/inbox-inspector/ I think most ESPs do t

Err, doesn't Mailchimp already offer that? http://mailchimp.com/features/inbox-inspector/ http://mailchimp.com/features/inbox-inspector/ I think most ESPs do these days.