The Geolocation API is a @W3C Candidate Recommendation http://j.mp/crgeo "believed to be stable ... encourage implementation by the developer community." longlink: http://www.w3.org/TR/2010/CR-geolocation-API-20100907/ The Geolocation API (often miscategorized by technomarketers as part of "HTML5") is the first of the Open Web App APIs that has reached CR - quite a big deal, given that all the rest of them are still merely Working Drafts (or Editor's Drafts). Even HTML5 itself is still just a working draft. And this is a perfect example of why it's important to be precise about what is "HTML5" and that is one thing: http://www.w3.org/TR/html5. All those other things like CSS3, Javascript, other APIs etc. that we use with HTML5 to build Web Apps are better referred to as "related technologies."