Looks like this is a bit of an older product. I'm actually disappointed in myself for how long I waited to look for something like this. I hate trying to keep track of all of my online purchases when they're en route.
Parcel does the work for me. Enter in your tracking #, carrier type (over 240 supported) and a brief description, and you're good to go. The free version supports up to 3 concurrent shipments, but for $1.99/year you can track unlimited packages.
Simple, but effective.
@stttories yup, that's it. It is worth the $5 if you also get the desktop widget for OS X. Basically the developer is very active and committed this app — I've used it for years — and it keeps getting better. So yes, worth the money.