TOR network is the inbetween between P2P and centralisation. TOR relies upon exit nodes and relays which are hosted purposefully by people all over the world. It's decentralized only in that there's random people to host the servers instead of paying for them yourself, but the clients do depend upon those servers.

Due to the usage of lots of servers the source IP is not easy to get and associate with any specific content. However if you control a relay and exit node, and data passes through those, you can put the dots together.(1) If a platform uses TLS you probably can't track though.

This is true of any server that proxies requests.

1. https://blog.torproject.org/one-cell-enough-break-tors-anony...