— Eric Enge and Stephan Spencer and Jessie Stricchiola and and Rand FishkinLogfiles contain a detailed click-by-click history of all requests to your web server. Make sure you have access to the logfiles and some method for analyzing them. If you use a third-party hosting company for your site, chances are it provides some sort of free logfile analyzer, such as AWStats, Webalizer
Replicated under Fair Use from The Art of SEO by Eric Enge and Stephan Spencer and Jessie Stricchiola and and Rand Fishkin.