Using Webserver Log Files and Analytics to Discover Keywords
Your website analytics software and webserver logs can help you determine keyword phrases you should optimize for.
Webserver Logs Explained
Most webservers such as Apache and IIS log most requests to the websites they host. One use of this information is to allow a webmaster gain insight into how people find and navigate his website. It is even possible to find out the search engine and exact keyword phrase a person has used to find the website.
Webservers and Log Files
Many web hosts provide raw log files of all requests to your website. Some also includes an interface such as AWStats. If they only provide raw log files, you can access them through FTP and view them later in Analytics software.
Look for Search Engines and Keywords Used
When you have found out which keywords people use, start digging more. See which pages rank for what keywords. Now use keyword analysis software to find related search phrases. Find keyword variations with many searches and weak competition. From here you can create new pages or modify existing ones to cover more search phrases.