From Newsgroup: alt.fan.usenet
There's a site that keeps statistics on Usenet providers, the number of
groups they carry, and the header retention of each provider on a per
group basis. They don't cover every provider but they do have a mixture
of paid binary and text and free providers.
https://www.uzantoreto.com/
They list a total of 445,994 known Usenet groups. Out of these, Eternal September currently carries 26,313 groups. Other free text group only providers carry between a few hundred to around 40,000 groups. The
commercial paid providers all carry over 100,000 groups. Providers on the Netherlands based XS News Abavia backbone carry the most, currently
279,758 groups. This is 63% of all the known groups and 117,893 groups
more than the next provider down the list, Usenet Farm with 161,685.
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