I didn't have time to check if the following details have already been posted here but for what it's worth I found another hole in my browser that was feeding websites my geo location to help them personalize me.
In your Firefox browser address bar type in:
Then search for:
Double click it to change from default of broadcasting your IP to disabling it -- if you want to make it a wee bit more difficult for those profiling you for commercial purposes.
I know there are many other ways for sites to get it just the same but after testing it on a google search page they are no longer displaying my local location in the left hand column.