In Web2.0 URLs are not unique anymore...
… and that’s a problem because it makes RSS feed aggregation harder than it should be. Once upon a time, Tim Berners-Lee and a few of his close friends, invented the concept of a URL1, and in the early days of the web, the ‘U’ in URL could be taken to stand for Unique (although it’s always stood for Uniform). Thus, if you typed a URL into a browser address field, it would take you to one, and only one, destination....