One of my medical journal clients just found out the hard way that Constant Contact does not accept permission based email addresses from LinkedIn. The journal had over 2000 addresses from their Constant Contact list unsubscribed by the company that they deemed not acceptable. I was told that beside the sign up forms that they offer for the web the only other acceptable tools for sign up are the Facebook tool, text tool, QR Code and the APP market place. Now my client must do a personal request for each address to sign up directly. Very time consuming.