The topic of advertisements is definitely a sensitive one.  I think most
would agree that wholesale advertising on our lists, with no regard to the
topic of the advertisement relative to the topic of the list, is to be
frowned upon and prevented, if possible.  But past that it can be very
subjective.  What would be an advertisement on one list might be needed
information on another.  The solution would seem to be a knowledge of
one's list and expectations of the subscribers as to what the list should
be, and consistency (as someone else pointed out, you don't have a very
good case if B is not allowed to do exactly the same as A did).
 
We have many postings on our list from the Library of Congress about new
publications, schedules, etc., and they could be called advertisements.
But they are needed informational items to the profession and no one
would dream of complaining about them.  And they are usually discreet
statements of availabilty, if you want the items (there are often
questions about "when will the next xyz be available?  Has it already
been published and I missed it?" etc.)  But on your list this might well
be unwelcome advertising garbage.
 
There is also the matter of form.  For a scholarly list, a note like:
"The Journal of SuchandSuch will be late in publication this month."
might be ok, while this might not:
"The Journal of SuchandSuch will be late in publication this month.
 To subscribe, send $x to address."
 
And the mere announcement of the availability of a new book, on the
topic of the list, might be ok, while one with quotes of glowing
praise from prepublication reviewers might not.  Testimonials from
subscribers as to the value of the book might be ok, but you might
be suspicious if they are new subscribers.
 
We have never had any real complaints about job postings, as long as
they are germane to the field.
 
The same goes for conferences, even commercial ones, as long as they
are topical.
 
Items from new vendors in the field, trying to drum up business, are
another matter.  These are usually fairly blatant ads and the vendor
should probably be told to desist.
 
But, again, this is all subjective and depends on the list.  Doing what is
"right" depends on knowledge of your list, its expectations, and consistency.
 
At least, that's how I see it.
 
        Douglas Winship    Austin, Texas    [log in to unmask]