AuthorGear.com

Author Gear was developed in WordPress with a custom theme, custom plug-ins, as well as other custom functionality creating the world’s most powerful Kindle book builder and seamless review swap system.

Author Gear has four different membership levels to select from, each releasing its own privileges to the member. The ordering system was integrated with one click upsells and upgrade capability to current members.  There is also a built-in social element for members to discuss and interact with one another.

Just released recently, this site is also getting rave reviews on WarriorForum.