lucy24 - 1:09 am on Mar 14, 2013 (gmt 0)
Does piwik (company) collect data from the analysers installed on sites?
Not unless they're lying to everyone on a major scale. (I kinda doubt this.) In fact one of their selling points is that the database lives on your own website so there's no third-party involvement.
But I went back and checked. You're right, there is a tracking cookie. Entirely separate from the "do not track" cookie, so it does get a bit circular. Unless you go with the logs option, which I haven't explored yet-- mainly because I've already got my own log-processing code that does what I need. And no matter what you do, there's the noscript administrative gif that you can manually pull out of your own logs, should you so desire.
* Well, OK: "or their proxy IPs".