Re: >Geolocation API, possibly the most useful HTML API out there
The geolocation API does ask for permission, and does it on a per site basis, so in that regard, it's not really any different from allowing an app to access your position, as far as I can see.
And sometimes, it is just simpler to let the site work out where you are, especially if it's somewhere unfamiliar, or just to save time.
On one of my sites, we have a 'Visiting' option so people can update their profiles when travelling. You can enter city and country, or just choose 'Geolocation' and we'll work it out for you. As far as I know, there's no way a site can grab your details without a pop-up the first time you visit.