I like this explanation more (for layman like me): http://www.youtube.com/watch?v=g_IaVepNDT4&list=PLkahZjV5wKe_dajngssVLffaCh2gbq55_
Starting with this video and going on to the next few.
If you slow it down, smooth it out, and make it interactive it would be like virtual driving :). I've always wondered if google street view and maps could also be used to make massive interactive game worlds based on real world locations and geometry in a jiffy.
Except that savings accounts these days offer interest of what? Less than 1%? If you'd put your money into a savings account like the guy they were replying to suggested, you would actually lose money due to inflation being higher than the returns of almost any savings account available.