Google Analytics is the most widely used tool for analyzing website traffic and visitors. It is a free tool that any website owner can install on their website, and as soon as it is installed and properly configured, you get immediate data about who is visiting your website, where they came from, and what they do on your website. All data is anonymous, and the primary use for Google Analytics is to identify trends and to evaluate how effective your website marketing is.
As one measure of popularity, Google Analytics is used on approximately 55% of the world’s largest 1,000,000 websites.
One warning of caution about Google Analytics: it is a very useful, and very powerful tool, and every website in the world should make sure it is setup as soon as possible on their website, but it is also very complicated. You should resist the urge to spend too much time pouring over the data, unless you have a clearly defined purpose, and you are confident that the information you are looking for is actionable. Too often people waste time by looking for un-actionable information, and ultimately they lose interest. The best use of Google Analytics is to configure it in a way that it measures and quickly reports (you can receive email updates on a weekly basis, or login for the information) that show key metrics or Key Performance Indicators (KPIs) that are tied to revenue goals. If you align your Google Analytics implementation to measure progress toward goals (things like newsletter signups, purchases, email inquiries, etc.) then you will be thrilled with Google Analytics. But if you just aimlessly pour over the data, you will do nothing but waste time.