I came across Koko on the website of M4WP, a plugin that links your site with Mailchimp.
Koko advertises itself as a privacy-friendly, simple and lightweight analytics plugin for WordPress. It does not use any external services, so data about your visitors is never shared with any third-party. It says it lets you focus on the important metrics, while respecting the privacy of your visitors.
It also says that no visitor specific data is collected, only aggregated counts.
So some data is collected and if aggregated counts is in reference to your individual site then Koko knows how big your audience is, at the very least. That may not concern you or it may. At least we can say that whichever method you use, someone will be collecting data. For example, it says that using Koko means you can stop sharing visitor data with third-party companies who also happen to sell ads. Fair point, I think, maybe.
And it says that Koko will stop unnecessarily slowing down your website if using other methods. I can’t speak to that because what is the real difference? I guess an A-B test is the only way.
There is a free version in the WP Repository, and a paid version that in addition to the features of the free version – Pageview & visitor counts, Realtime pageviews, and Referrer URL’s – also enables Custom event tracking, Periodic email reports, and Email support rather than via the Support option in the WP Repository