Matomo
From Jon's Wiki
Matomo (formerly Piwik) for digital analytics. Measurement = improvement.
Continuous improvement: measure, report (easy), analysis, test (less easy), repeat.
Why Matomo and not Google Analytics? Data privacy. Compliance with EU cookie law and new GDPR rules. Not data limits or sampling. Open source, customisable, community plugins.
Start with a goal. Choose the required metric, collect data. Monitor performance over time.
Create and customize multiple Matomo admin dashboards for different user needs. Arrange widgets.
Campaign: e.g. send a newsletter. Links to the site should include a campaign pk_campaign parameter (Matomo will aggregate automatically, no need to define), e.g.
https://wiki.jon.geek.nz/Something_interesting?pk_campaign=NewsletterApril2018&pk_source=newsletter