Afaik with Usenet it is essentially everybody gets everything PIR, in that everybody gets every message for the group or whatever. I am not sure though I never used Usenet but have read about it in the context of remailer networks. I think the original design for a PIR based anonymity system was actually intended to be an improvement on usenet. In the old model it was remailer to Usenet, then download the entire Usenet set of messages and filter for the ones you want. Pynchon gate brought down the bandwidth requirements by orders of magnitude by replacing Usenet + everybody gets everything with a simple distributed PIR that was not everybody gets everything. I agree the only person that should censor what you see is yourself. And you should be able to do so easily and in a way that is scalable (ie: not downloading all messages and then ignoring them, but never downloading messages you want to ignore in the first place). All of these things can be done with PIR like systems (I am more interested in PSS and OWI but really all of these fancy new things are like extensions of PIR, other than EKS I suppose which is like PSS without the PIR-like aspect). But really it isn't even a requirement for it to be PIR-like, it just needs to be pull instead of push. The same thing helps for anonymity as well, the main reason Pynchon Gate is superior to Single Use Reply Blocks (SURBS) is because with a SURB based remailer an attacker can push messages to you but with Pynchon Gate PIR the clients pull messages of their own choice. This prevents an attacker from spamming you with a billion messages and then watching to see which node gets a billion messages pushed to it, since with Pynchon Gate PIR if the attacker spams you wil a billion messages you just don't pull any of them. I made a pretty good basic design for a whitelisting messaging system I think, it is inherently whitelisting in that by the very nature of the system users cannot communicate with each other until they both have accepted to whitelist each other. Invitations to whitelist can be carried out through shared contacts as rendezvous, after an initial out of band social bootstrapping to get a few social contacts using the system. I think Freenet is the most interesting and innovative of the anonymity networks personally.