The now widely popular Google Analytics system is now being used around the world for accurate reporting of website statistics and metrics.
I have a word of caution: Take this with a grain of salt.
There’s a simple reason: cached pages. Google Analytics shows statistics for your cached pages only. Many people overlook this when using numbers and statistics from Google Analytics. Even those who use this system on a daily basis may forget this simple truth.
The reality is that even if you have great site maps, a good crawlable website, and a high google indexing rate, you may still have pages, even entry pages to your site, that are not being counted in the Google Analytics number. That is one reason why there is such a disparagement of data when comparing two analytics tools. For example, Google Analytics will always show a much lower hit count than a log-file based tool like ClickTracks that counts every visitor to every single page.
Now, before you go out and dump your Google Analytics, be aware that even log-based tools like ClickTracks are not fool-proof. Log-based analytics systems can skew numbers by counting visits to pages multiple times while Google Analytics does a good job of tracking the user through their entire website visit experience.