Signing up for Twitter at South by Southwest 2007, I can remember those feelings of "Wow, this is going to be big." That instant feeling of knowing you're seeing the future and the world doesn't even have a clue yet. It'd be years before my friends would finally take the leap and get their own Twitter accounts (even if I knew Twitter usernames in 2007 were like domain names in 1995 ). There have been other services I’ve though would be big, but only one other time in the past four years have I been awe-struck. That other moment was earlier this year (SXSW 2011) when Foursquare unveiled v3 with the "Explore" functionality—I knew that was a life-changer. I've dug Foursquare since the early days, but this third version is where it became obvious that every person in the world would benefit from using this service. The third magical "wow" moment just happened this week, and it's Turntable.fm . The early adopting tech elites are eating this site up, just as they did Twitter, Foursquare, Instagram, and others. Barring some awful interference, this app is going to break big and change things.