They collect data about you from every website that you visit that uses Discourse. They share it with a lot of other organisations, including Google analytics.
Do you just want to trust them, pinky promise, they they aren’t (for instance) compiling a record of all your comments on Internet forums, and sending them to job recruiters and HR?
No, they don't collect data from Discourse installs when you host them yourself.
> CDCK sets only its own privacy practices, not the privacy practices of CDCK customers or others who host Discourse forums for themselves or others. You should ask all of those involved in administering and hosting Discourse forums that you use for information about their privacy practices.