Most importantly firefox doesn’t share your location without your permission and is done with the utmost respect for your privacy. And, like all elements of Firefox, it’s being created using open standards to ease adoption by Web developers.
Websites that use location-aware browsing will ask where you are located, in order to bring you more relevant information or to save you time while searching. Let’s say you’re looking for a pizza restaurant in your area. A website will be able to ask you to share your location so that simply searching for “pizza” will bring you the answers you need… no further information or extra typing required.