Rated 5 out of 5 stars

Από τον/την binba στις Νοέμ. 19, 2009 · μόνιμος σύνδεσμος

This add-on was so nifty and useful, it made me sign up just to post the review :-)
Simple, does what it's supposed to be, that's what it takes to get 5 stars.

My only missing feature: add support to use the app via the search engine bar, for tracking numbers that aren't in a web page.