April 7, 2010 update

I have looked into Piwiki and found the Mediawiki Piwik plug-in to access Piwik-results as a "Special page". (Extension:Piwik_Integration)

Thanks! Have you played with it on an installation of Mediawiki by any chance?

Now, I´ve installed Piwiki on my local mediawiki. Piwiki is functioning, but I don´t see the Piwiki-specialpage in the Wiki. I will try to learn how to write a plug-in, but I´m not an experienced programmer.

Excellent! Let us know your experiences here; would love to hear if you find it useful. Nimish is going to install it on an internal wiki as well. Looking forward to sharing notes.