Well there are a number of patents and recently Nielsen/Netratings sued Omniture (http://www.omniture.com/press/242 http://www.omniture.com/press/242) and Corem

Well there are a number of patents and recently Nielsen/Netratings sued Omniture (http://www.omniture.com/press/242 http://www.omniture.com/press/242) and Coremetrics (http://www.internetretailer.com/internet/marketing-conference/274569896-netratings-files-patent-infringement-suits-against-coremetrics-omniture.html http://www.internetretailer.com/internet/marketing-conferenc...) The number of patents is surprising, so far I have found 24 patents we seem to be violating, among them: Content display monitoring by a processing system http://www.google.com/search?q=Patent+7386473 http://www.google.com/search?q=Patent+7386473 System and method for analyzing remote traffic data in a distributed computing environment http://www.google.com/search?q=Patent+6112238 http://www.google.com/search?q=Patent+6112238 Online Traffic Sampling http://www.google.com/search?q=Patent+7185085 http://www.google.com/search?q=Patent+7185085 And plenty more.