Sender ID is a standard for authenticating email developed by Microsoft. It is used by ISPs to ensure that purported senders of email messages are actually the ones presenting the messages they review.
AWeber authenticates using Sender ID
In order to ensure optimal deliverability of messages, AWeber does authenticate using Sender ID.
For more information on Sender ID and other standards that affect the deliverability of email messages, review the complete article on email authentication.