There are many web services who offer to track your websites stats such as: hits, referrers, geo tracking, browsers, keywords, etc. Some of them, like extremetracking.com make this information public. Searching google for "Unique Visitors"+site:extremetracking.com will pop some interesting results to look into. This can actually help with your SEO skills. You take a website which uses extremetracking, check how they optimized it, check backlinks and then check keywords and visitors and see how well is it doing. Have fun!