Sure, you see them sitting around near ports and rail ramps. But how exactly are containers used for shipping? Check out this video that shows how goods go from a factory in China to a Target in California. You can see how they are filled up, loaded on ships, taken out of the port and brought to the store. http://www.youtube.com/watch?v=L1nZNIeF2uc
Once the container is emptied out, it goes to a container yard to be stored until the shipping line needs it to bring something from that location to another.
For additional fun, watch this Port of Long Beach crane operator move containers around:
It is amazing how versatile containers are and how efficiently they are moved around the globe.