I've always wanted to know where the people who follow me on Twitter are from, both out of curiosity and so I can connect with them as I travel around the country. To find out, I built a tool using OpenHeatMap to visualize your followers by location. It only shows followers who have been active recently, but I've had great fun discovering connections to Ghangzhou, Prague and even the exotic, enigmatic country of Canada, little known to westerners.
There's actually three different views you can use to explore Twitter as a map. You can put in your own or someobody else's handle to see their active followers, you can visualize the updates from the people you follow, or do a search on a keyword and see where in the world people are talking about that topic.
It's still just a prototype, but it feels like a step towards the interface we need to make sense of the flood of location data that's flowing all around us. I look forward to hearing your ideas on improving it, and since the component is completely open-source, feel free to build your own to show me how it should really be done!