Interesting thread...
I use satellite mapping and GPS mapping daily. It may interest you to know that by the end of this year there will be sattelite data available to anyone in the public who is willing to pay, and will have one-meter pixels. Which means that the smallest viewable element in the image is about three feet. Further, the revisit rates are scheduled for every 36 hours (by the end of 2000); meaning that you, member of the paying public, can see how things change on the same three feet of ground in full color every 36 hours. The *funny* thing is, that this isn't necessarily Big Brother watching, its us watching each other...