After a recent online order confirmation, I checked the major engines to see which can link directly to the shipment tracking page by entering in the US Postal Service tracking number into the search box.
The results: Google and Windows Live tracked it. Yahoo and Ask.com returned no results. Google-powered AOL and MySpace (when searching the web through it – and MySpace IS a search engine) also didn’t return anything.
This is a minor benefit for Google and Live, but any search that goes unfulfilled, especially at the fault of the engine and not the user, erodes its credibility. Search technology’s an arms race and no one can afford to be left behind.