In what is being termed location-aware web browsing, Firefox is boasting location provisioning in release 3.5. The idea is that users will be asked where you are in an effort to deliver more relevant, local content to your search results. When using mapping functionality, the idea is that the browser will know where you are so all you need to do is enter where you want to go in order to get directions etc… Location browsing is totally optional, however, you can set it up by entering the following in the url browser bar – Type geo.enabled
See more at http://www.mozilla.com/en-US/firefox/geolocation/