Locative information is one of the most practical and heavily used aspects of information science. iPhone users are showing up on Twitter with new apps allowing their iPhone to pinpoint where they are and seek out others using the system. Lots of us use GPS to get around and I don't know about you, but the last conference I went to, my GPS was incredibly useful. Not only could I get around, but I could find bars, restaurants, bookstores, and anything else I needed.
The problem is, GPS only works on the Earth... which could be an issue if we're thinking about going back to the moon.
Now granted the moon is only about a quarter of the size of Earth, but you could still get lost pretty easily and it's not like there's anyone about to ask for directions. So NASA needs a plan... and it turns out that they have one.