There are a lot of tools to help collecting data or analyzing a website in the internet. For more information see also Web Controlling Tools.
WebTrends, or FlashStats and WebSuxess are tools for analyzing log files. Alternatives are freely downloadable open source products such as Webalizer, Analog, AWStats. Numerous analysis tools for search engine optimization (SEO) such as Google Analytics can be used for index-evaluation, improvement and also for monitoring the success of advertisements.
An alternative to the powerful Google Analytics tool is Piwik, which can be adapted as an open source software in business on their own requirements.