Track a Package in GMail

I just noticed a really cool feature in GMail.  Check it out. I recently ordered an item from Amazon and today they sent me an email confirming the shipment of my order which contained a USPS tracking number. GMail recognized that the number was a USPS tracking number and added a link to the sidebar, just above the sponsored links, asking if I'd like to track my USPS package.  So, instead of having to open another browser tab, enter the USPS  web address and copy and paste the tracking number, I just have to click the link provided by GMail and I instantly have the status of my shipment.  Pretty cool huh?