Google Analytics

Google Analytics (GA) is a free service offered by Google that generates detailed statistics about the visitors to a website. Its main highlight is that the product is aimed at marketers as opposed to webmasters and technologists from which the industry of web analytics originally grew. It is the most widely used website statistics service, currently in use at around 57% of the 10,000 most popular websites.

Google Analytics is the enterprise-class web analytics solution that gives you rich insights into your website traffic and marketing effectiveness. Powerful, flexible and easy-to-use features now let you see and analyze your traffic data in an entirely new way. With Google Analytics, you're more prepared to write better-targeted ads, strengthen your marketing initiatives and create higher converting websites.

Google Analytics is implemented by including what is known as a "page tag". This is referred to as the Google Analytics Tracking Code (GATC) and is a hidden snippet of JavaScript code that the user adds onto every page of his or her website. This code acts as a beacon, collecting private visitor data and sending it back to Google data collection servers for processing. Data processing takes place hourly, though it can be 3-4 hours in arrears of real time. However, a comment on a web analytics blog from a Google employee indicates that not all data is processed for approximately 12 hours after collection.

To function, the GATC loads a larger file from the Google webserver and then sets variables with the user's account number. The larger file (currently known as ga.js) is typically 18 KB in size and is only downloaded once at the start of the visit as it will be cached throughout the session. As all websites that implement GA with the ga.js code are using the same master file from Google, a visitor that has previously visited any other website with this code implemented, will also have the file cached on their machine. The result is that the page overhead of including the GATC on web pages is kept to a minimum.

In addition to broadcasting information to Google servers, the GATC sets first party cookies on each visitor's computer. This is used to store anonymous information such as whether the visitor has been to the site before (new or returning visitor), what is the timestamp of the current visit and what was the referrer site or campaign the visitor came from e.g. search engine, keywords, banner, email etc.