This was a pretty fun project. The server generates a stream of data that we then use client side to render all of the content. Of all the new features we added, the one I would recommend checking out is single URL view. Click on any url to get a single URL view that includes a moving bar graph (that fills in with data as it happens) along with the search terms and copied terms for that specific page.
Read more about it on the AddThis Blog and then go log in and start seeing how people are using your site right now.