Piwik (previously known as "phpmyvisits") aims to be an open source alternative and direct competitor to the famous statistics from Google Analytics. As both programs are free for its members, the main fight for the users will be on the level of the usability, user interface, and set of features available.
Piwik provides detailed reports on the web site visitors, enhanced statistics per pages popularity, overview of search engine keywords, languages used, traffic origins, and much more. If in US it is just starting its way to the consumers, in Japan it is already well-known to the bloggers and website owners.
What makes Piwik different:
* Open APIs
* Plugins Architecture. New features can be added and unneeded stats can be dropped. In its basic format, there are four different categories - dashboard, visitors, actions, and referrers. Each section includes multiple analytical widgets that can be added and removed easily. Outcomes can be presented as bar graphs, pie charts, or plain text.
* Data abstraction layer
* Customizable dashboard.
* Innovative customizable User Interface. You can drag and drop the widgets you want to display and create the reports you want.
Note, that Piwik should be installed on your webserver, while all the data is stored in your own database.
Give it a try: http://piwik.org/