Twitter Earth allows you to view from where people uploaded different Twitter messages and filter them by topics.
Here is how it works: you type a keyword in the pop-up window that appears on the top of the browser. Based on your input, Twitter Earth will search on Twitter the messages that are based on your current location according to Google Earth.
The resulting Twitter message locations are displayed within the Google Earth world view. Twitter messages can be filtered based by keywords or topics within the Twitter messages.