Junecloud's Deliveries is a fantastic little app to aid in tracking shipments that you are expecting or sending. It got its start on OS X's Dashboard feature ages ago, a feature which is being phased out in OS X Yosemite.
When the App Store came out for iOS devices, Deliveries was there. I've been using Deliveries in Dashboard on my Mac and on my iPhone and iPad for years. It is simply an indispensible and delightful little tool.
With OS X Yosemite eschewing Dashboard by default in favor of adding widgets to Notification Center's Today view, I was hoping to see Deliveries make the transition. Thankfully, I was not disappointed. Deliveries is now a full-fledged Mac app with Notification Center integration, and it also allows me to say farewell to Dashboard, which has been stagnant for years on the Mac.
If you happen to receive shipments frequently and want to keep tabs on them, you need Deliveries.