"Updated “Who does Plex share or sell Personal Data with?” to include the Plex activity that you share based on your account visibility and activity settings as well as sharing/sale of certain Personal Data to third parties.

Nothing changes for Plex Accounts created before March 20, 2025 unless you change your preferences here.
If you are a new user and created an account after March 20, 2025, you can update your preferences here.
The types of data that we may share has not changed
We do not and will not collect information about content or titles in your personal media library or what you’ve played.
Personal media users: we do NOT, and will not, share or sell any information about the content and titles on or your use of a personal media server.
Consent is required by all Plex Accounts created before March 20, 2025 for the sale of their data."

Seems like it’s just for their other services, which I already assumed they were tracking and selling view counts.