Twitter's just launched a new portion of their service called Explore. It's essentially a "labs" section, and home to a handful of old (and new) tools to integrate and browse Twitter. The newest addition, called "Blocks," is a 3-D visualization of your friends and followers, and what amounts to a 3-D social graph of Twitter buddies. The tool loads up with a neat popping effect that looks like little rooftops, and similar to the neat startup video on the Apple TV. Each one is actually a message. Mousing over it will show you who wrote it, along with who wrote any surrounding messages. Clicking on it zooms you down to see what it says. One you're there, you can quickly navigate from message to message using your keyboard's arrow keys.