Google Analytics
Google Analytics is a FREE web analytics service offered by Google, Its an increasingly powerful product originally aimed at marketers as opposed to webmasters and developers.
Using JavaScript page tagging combined with cookies Google Analytics tracks the standard analytics data. Such as unique visitors, page views, average session times, traffic sources including referrers, search engines and direct traffic. As well as goal and conversion funnel analysis, Google Analytics have recently introduced advanced customer segmentation and custom reporting that put it ahead of many of its rivals making a serious option for both web analytics experts and the less experienced website manager.
The main advantage offered by Google Analytics is the large community of marketers and developers now familiar and using the product. The service also has the ability to integrate with Google AdWords straight out of the box but can be easily configured to track other marketing campaigns. Campaign tracking enables users to review online campaigns by tracking landing page quality and conversions such as sales, lead generation, viewing a specific page, or downloading a particular file. Using Goggle Analytics marketers can determine which campaigns are performing, and which are not, helping to maximise return on marketing spend.
Like many web analytics services Google Analytics uses a high level dashboard-design to provide overviews of data and more in-depth data by drill downs into the report set. Users can officially add up to 50 site profiles. Each profile generally corresponds to one website. It is limited to sites which have a traffic of less than 5 million page views per month (roughly 2 page views per second), unless the site is linked to an AdWords campaign.
Recently Google released the Google Analytics Data Export API. The API allow developers to export Google Analytics data for integration into existing products and standalone applications. Go here for more information of the Google Analytics Data Export API
more information:
The Official Google Analytics Blog
The Google Analytics Help Centre