They host some: https://archive.org/details/usenet https://archive.org/details/usenet As far as my own old posts are concerned, it looks complete :) But it isn

They host some: https://archive.org/details/usenet https://archive.org/details/usenet As far as my own old posts are concerned, it looks complete :) But it isn't easily findable or searchable; the intended way of interaction is apparently to download an entire hierarchy and grep.