For most everyday users, i.e. non-enterprise, add ins that work within Outlook are not a norm.
In fact, many do not realize that these feature adding/enhancing programs and apps even exist.
Package Tracker keeps an eye on your inbox and when it sees an email that includes shipping and tracking information for a package it goes into action.
The add in gives you that tracking information directly in the reading pane of your email.
The nice thing about this add in is it works with the Outlook Web App and on the desktop version of Outlook.