I've read the forum policies carefully and tried to contact admin folk via email to ask this question (I forget now why that contact attempt failed). I hope I can get this answered here.
Let's hypothesize that a forum member has written a book that s/he deems pertinent to the overall community, and wishes not so much to "advertise" as to simply "announce". I.e., a one-time announcement that this new book is out there, briefly what it's about, perhaps a link to where it can be found. Placed in one and only one most-pertinent sub-forum (Backcountry Books I guess).
Is that "advertising" and disallowed? I've seen cases where it's clear that a friend is acting as a shill and thus bringing up someone *else's* book, but that's just an end-around to accomplish the same thing --- but a bit less honorably. I feel a bit awkward about this, recalling the famous Admiral Hopper quote (easier to get forgiveness than permission), but best is if policy allows what should be allowed and vice versa.
If there's simply no way to do it on this site, so be it. I would --- hypothetically you understand --- like to understand the rule here.
Ah, and one other question. Let's further hypothesize that this hypothetical eBook at some point is available for free for one, or perhaps two days only. Is it also disallowed advertising for the author to let folks know that the book is temporarily free to download?
Awkward questions, I know! Thinking of this from the perspective of a typical forum member, I guess my own reaction is that I can tell when something is over-the-line advertising/spam but I can't easily and crisply define the boundaries. If a one-time (and in just one place) announcement of a new book comes out (whether by the author or by someone else) and the book is clearly very relevant to the overall purpose of the site --- then I'd be okay with it, but not much more.
Thanks for any feedback on this.