AWeber uses a content filtering tool called SpamAssassin™ to help you avoid content filtering. This tool is widely used by ISPs to filter incoming email. To see the breakdown of your spam score in a Draft, click on the spam score provided for your message.
It will also show for Follow Up Messages.
SpamAssassin™ will provide you with a breakdown of the score. The more items in the message that trigger the SpamAssassin™ rule set, the higher the spam score will be. Any message with a spam score of 5 or less is okay to send.