Not sure about being the middleman yet. What if the big Usenet providers decide to delete data or we violate their non-business-usage policies? But on the other hand it's really cheap indeed! We can cancel our Usenet subscription and renew it when the data is needed. So I thought it's maybe better to cut out the middleman by giving the software away.

About the abuse: I imagined that the method could be used like some unlimited-disk-space-providers which had to get rid of that plan because the users used it as advertised.

Of course, apart from that, anyone can write such software. So it's maybe just a matter of time? Though I couldn't find any other solutions besides RAR archives.

The Usenet can be used as a key-value store with handicaps. And stuff can be built on top of that.