There are many different places to share content on the web. AddThis calls these sites Services — a "Service" is just a web page that can accept shared content on it’s URL. The Service Directory includes all of the services AddThis knows about. It lets publishers, users, and service owners see where sharing is happening on the web, and suggest new destinations.
AddThis uses the Service Directory, along with deep analysis of sharing activity, to provide users with smarter, more contextually relevant choices for sharing content to specific services. AddThis helps to put the right services in front of the right user at the right time.