In 2004, ten years after Netscape launched, Tim O'Reilly launched the 'Web 2.0' conference, proposing (or branding) a generational shift in how the web worked. There were lots of trends, and none of them really started in 2004, but to me, looking back, the key thing was that people said 'if we forget about dial-up and forget about supporting old and buggy web browsers, and presume that lots of peo