Ont thing that hasn't been mentioned yet is that it is essentially closed now. You can't just set up your own USENET server easily, because you have to pay someone $$$ to get federation (if at all possible). They will try to keep competitors out, because they sell access to newsgroups for a lot of money so people can download warez.

I think it should be possible to get replicas of non-binary newsgroups, but a quick search hasn't found any free option.