Absolutely nothing! And thats what he _should_ have done. But that
implies that he (and all the other people who post one-off ads like
that) has sufficient knowledge of newsgroups to be aware that that is
the 'proper' way of doing things. Trouble is, thats not likely to be
the case - commercial advert posters in groups like this, especially
ones where the readers are a 'band' like they are in this group, are
_usually_ ** completely new to the world of usenet. They're ignorant
(in the nice sense of the word!) of newsgroup etiquette, probably of
the internet in general, and are sitting there thinking "how do I
attract business". Then someone tells them about this wicked thing
called newsgroups, which is sorta like emailing your customer database
since everyone who gets your message is someone interested in Landies!
Wow, why didn't someone tell me before? Thats the _perfect_ place to
advertise (whatever it is they sell)! They've not read the group over
a period, why would they, as far as their knowledge extends they
already know for sure this is just the place for them. Unfortunately,
it usually has the opposite effect, since more knowledgeable users
simply steer away from such advertisers.

Indeed :o)

** Of course, there will always be a small element who are well aware
that the group dont want adverts but who post them anyway, hoping to
claim the naive tag if needed. But they're usually easy to spot, if
only because they repeat it as needed!!