By using Google Analytics, Statcounter, AWstats or one of the many other free statistic packages out there. I would use Google Analytics. It's simple to use.
Google analytics is also 30-40% inaccurate in many cases. I would go with awstats or any other weblog based analyzer if I have the option. i love the analytics interface but you can't find out how many images you are serving and also loose out many times when the javascript doesn't load in user's browser.
It's nowhere near 30%-40% inaccurate. The only inaccuracies come from people that block javascript etc, which accounts for maybe 1% of internet users.
GA's the best free one out there in my opinion. Analytics packages work on log queries, so it all depends on how the developers are structuring their queries which determines the numbers we see on the front end. There's pretty much always a 20% difference at least in uniques between GA and Omniture, for example. GA is pretty much the standard these days though, so I'd go with that.
Yes because webmaster either use google analytics or statcounter to check the stats of visitors per day and it is must.
You Cab Use Google Analytics And State Counter .. Google Analytics The Best Tool Monitoring Your Visitors.
Google Analytics is by far the best free solution, as long as you don't mind sharing all that data with Google. I wouldn't use Analytics on a site that I was using adwords/adsense on - its way to much info going to Google.