What is the use of Geolocation in HTML5?
It kind of localizes you or any other object, place or venue :) The fact that you can do this straight away without having to import any library and it works on every HTML5-compliant device is of huge significance. This is the real use of it :)
Some cameras detect areas where photos might be interesting to others, then ask if you want to share photos publicly. Retailers could use it to offer coupons, etc.