Very simple and self explanatory. Click on the little extension icon which looks like a bar from a bar graph and you get a drop down of the site your visiting in regards to their Google page-rank, Alexa page-rank and Geo-Location(which includes IP address, country and city if available). That is all on the top half. Below, you can choose from options of site information from varying sites and services such as Google Trends, Bing Indexed Pages, Google +1's etc. Incredibly interesting regardless of whether you actually need the information but for those who own sites and depend on traffic, keywords, placement and such should add this ASAP and make your life A HELL OF A LOT EASIER. At least in the part where you now can save yourself the time of going to each of the sites individually.