RSS, OPML and the XML platform.
Copyright 2012 World Readable
Dan Catt announced that Flickr has better support for GeoRSS. From what I gather, you previously had to ask for the GeoRSS info with an additional query parameter, but it's now included with each photo. But I'm unsure if this is in addition to other geo information available in the feed. Here's a sample XML fragment from an RSS <item>.
Note that the GeoRSS information is redundant and somewhat harder to parse. That's not a good first impression of GeoRSS. IMHO.