Wolfgang wrote:
... And I sure
would like to know how that "standard Usenet approximation" of 10 readers to
each poster was derived. ...

It's a guesstimate that works for most newsgroups in the Big 8.
I really don't know how it was derived but if you Google up
usenet arbitron readership you'll get more info than you want
to read.

--
Ken Fortenberry