Rand over at SEOMoz wrote an excellent post detailing all the different resources publicly available to gather statistical data on pretty much any web site out there. He breaks down the tools into several parts including "Technical Data," "Ownership/Hosting Data," "Statistics/Popularity Data," "Search Engine Indexing Data," "Link Data," "Social Tagging Data," "Third-Party Trust M with 0_àðøíresourcesfindingstatisticswebsite