In theory, someone with enough technical skills could create a script that tracks which IP is downloading which video. In practice, this is much more difficult because:
An HTTP request has to be sent on each tracker for each video to spy. If we want to spy all PeerTube's videos, we have to send as many requests as there are videos (so potentially a lot)
For each request sent, the tracker returns random peers at a limited number. For instance, if there are 1000 peers in the swarm and the tracker sends only 20 peers for each request, there must be at least 50 requests sent to know every peer in the swarm
The worst-case scenario of an average person spying on their friends is quite unlikely. There are much more effective ways to get that kind of information.
The threats to privacy with YouTube are different from PeerTube's. In YouTube's case, the platform gathers a huge amount of your personal information (not only your IP) to analyze them and track you. Moreover, YouTube is owned by Google/Alphabet, a company that tracks you across many websites (via AdSense or Google Analytics).
Your IP address is public so every time you consult a website, there is a number of actors (in addition to the final website) seeing your IP in their connection logs: ISP/routers/trackers/CDN and more. PeerTube is transparent about it: we warn you that if you want to keep your IP private, you must use a VPN or Tor Browser. Thinking that removing P2P from PeerTube will give you back anonymity doesn't make sense.
PeerTube wants to deliver the best countermeasures possible, to give you more choice and render attacks less likely. Here is what we put in place so far:
