Top Web Properties
comScore does provide some free materials such as the Top 50 web properties in the United States. I recall these lists, a long time ago, would only come with a listing of the sites in order. This particular list, as you will see, also comes with commentary and analysis from comScore which is very interesting. Here is a direct link to the page on their site which does not have the information but has a link to a pdf file, I am not sure why they did not post the information on the page but nonetheless you can obtain the PDF.
I for one think the analysis section is very helpful and they have interesting insights. They discuss the impact of political news, online gambling and humor sites in detail. Also broken out are the top sites ranked by those which had the most unique visitors, Google Sites, Yahoo! Sites, Microsoft Sites, Facebook etc., they are all listed out. Also they list the top ad networks in order of those that reach the largest audience, Google Ad Network, Yahoo! Network Plus, AOL Advertising and others. I will not steal their thunder, so take a look at the comScore 6 page analysis.