Offers nice free stats related to web site traffic and internet advertising. Basic abstracts and some stats are free, detailed reports are fee based.
Site offers other resources including a how-to section with a number of internet marketing topics.
This site contains Internet survey results beginning in 1994. A nice source to find trends in the Internet. Includes consumer and commercial surveys. Summary is based on research by work done at the University of Texas' Center for Research in E-Commerce. Generally kept up to date.