Google Analytics

Very very helpful tool, especially if you're running an online business. It may take some time to get to fully understand how it computes the stats, but all one needs to know is to interpret them and utilize them to strategise

I have configured Google analytics for my company's site, but its showing keyphrases of organic results as not provided which is not a good part of it.

Google Analytics should probably be used alongside another service – Google Analytics uses a something called Page Tagging (using javascript) to measure traffic. While this method is fairly effective for measuring unique users and tracking events that don't involve making requests to a web server (eg, flash action scripts), it is not good for measuring page views that occur when a page is (1) already cached in the user's browser or (2) being viewed in a browser that has security settings that block this sort of tracking.

Another way to measure traffic is through log files, used by services such as Awstats. Log files may give a more accurate page view number but a less accurate unique visitor number.

In conclusion, if you use Google Analytics (it has a nice interface, and is good for setting Goals and coordinating with Ad Sense/ Ad Words) it may make sense to use it alongside one of these other services.

Here's a good article on the topic: http://www.developmentseed.org/blog/analytics/faceoff_google_serverlogs