TL;DR Perennium is not going to do anything that I think might cause harm to the users. Perennium will also not collect more info than most websites do.
Activity on the website is tracked using Google Analytics which I believe is standard to most websites that don't create their own data-gathering services.
Profile pictures in their current form are identicons (basically: automatically-generated unique shapes for each user) created using Jdenticon.
Cookies are used to track whether you're logged in or not.
If you have any questions about the terms, contact me at: email@example.com.