Piwik is the leading open source web analytics software, but there are dozens of other free and paid web analytics solutions; why choose Piwik? One of the principle advantages of Piwik is that you are in control. Unlike remote-hosted services (such as Google Analytics), you host Piwik on your own server and the data is tracked inside your Mysql database. Because Piwik is installed on your server, you enjoy full control over your data. You can access the data easily via the Piwik APIs. Advanced users can use Custom Variables, Segmentation, or even run manual queries on the database in order to build advanced reports.
Piwik also protects your visitor privacy with advanced Privacy features. When using Piwik for Web Analytics, you ensure that your visitors behavior on your website(s) is not shared with advertising companies.
To help you decide on a Web Analytics software, you might want to look at the list of features in Piwik or the online demo. Piwik offers nearly all features that other tools may offer, and also has some unique features such as Real Time visitor details, Ecommerce Analytics, Visitor Profile, Real Time Visitor Maps and an awesome Mobile App. Finally, our Roadmap is public, and the community can check our progress on the public issue tracker.