privacy policy: add opt out link

website/privacypolicy.md

@@ -9,8 +9,10 @@ We use a self hosted instance of [Matomo](https://en.wikipedia.org/wiki/Matomo_(
 
 ### How
 
-- Visitors' IP addresses are **anonymized**. The last byte is masked and fully qualified addressess **never** reach Matomo.
+- Visitors' IP addresses are **anonymized**. The last byte is masked and fully qualified addressess **never** reach our analytics software.
 - User IDs are replaced by **pseudonyms** to avoid directly storing and displaying personally identifiable information.
-- We ignore any existing tracking cookie and our tracking **doesn't use any cookie**.
+- We ignore any existing tracking cookie and our tracking **DOES NOT use any cookie**. (See also: [What are cookies?](https://www.cookiesandyou.com/))
 - We honor your browser "I do not want to be tracked" preference.
 - Data is aggregated and reports are compiled. Raw logs are regularly cleaned up.
+
+You can opt out by clicking [here](https://stats.gbdev.io/index.php?module=CoreAdminHome&action=optOut&language=en).