Parcel Service:   this is the tracking that most shippers are familiar with, and it is by far the best system.  The notices that cargo is received goes out in minutes and as cargo enters and departs terminals it is updated immediately.  

Truck Freight:  tracking is done through a "PRO" number system.   The cargo will not be shown as picked up until it arrives at the terminal.  Often the cargo is well on its way before that is displayed on the tracking.  

Air Freight:  this is similar to truck freight, where the information is limited and is delayed as compared to the Parcel Tracking provided by United Parcel Service (UPS) and Federal Express (FEDEX).  Instead of minutes, it will take hours for the receipt and movement of cargo to be reported at some terminals.  Most of the time the cargo is just sitting at a cargo terminal waiting to be loaded.  If cargo for a particular flight fails to arrive, cargo can be moved up and go out sooner.  Most of the time what happens is that there is an excess of general cargo so the carrier will sell "PRIORITY" or "PLATINUM" rates to customers who are willing to pay more, and then the GENERAL CARGO will get bumped so that the carrier can make more money.  

Ocean Freight:  the cargo is tracked through the Bill of Lading Number.  Most of the time, the freight or container is just sitting at a terminal, port or on the boat, so there will be days without any update on the location of the shipment.  This site  tracks the GPS locations of ocean vessels.