As much a novelty as a data source, Worldometers uses statistical averages and your computer's clock to calculate a variety of figures about human beings and the planet we live on. These are basic javascripts (meaning that, if you really want to have a self-incrementing world population meter on your site, the code is right there), and should work on any standards-compliant browser. The site reports some problems with KHTML browsers like Safari, but it seemed to work fine for me...
(Via information aesthetics)