I'm just a relatively new moderator here, and Packlite, the administrator and owner of the site, has the final say. In other words, nothing I say here is 100% official. However, the following is how I've interpreted the advertising policy. Anything that seems borderline I refer to the other mods and Packlite through the moderators-only section of the forum.
I would consider an up-front announcement just fine. We do it for others (such as posting "Cottage manufacturer XYZ has just come out with a 20*F sleeping bag that weighs only 0.2 ounces"
). Wandering_Daisy made a one-time-only announcement here when her Wind Rivers guidebook was available (several of us had been asking) and, as I recall, she provided the URLs for the websites. Such an announcement, in my mind, is information, not advertising.
We also get the occasional new product "startup" trial balloons in which we are asked for feedback (not counting these "Survey Monkey" things which we've just taken steps to ban). To the best of my knowledge, we've encouraged these. Once the product is actually for sale, though, continued promotion of it by its manufacturer in the forums would be considered advertising.
Continued free advertising in the forums is a no-no because it deprives this site of advertising revenue needed to keep it going. This would need to be negotiated with Packlite.
I don't see anything wrong with a one-time announcement of a free deal or reduced price, either, but that would also be a Packlite decision.
We have occasional feedback from manufacturers such as Tarptent responding to questions asked in the forums about their products, and that, IMHO, is great. I've never seen Franco or Henry wander off into advertising their products when they do this, and they do state their connection with Tarptent.
Of course nearly all the forum advertising we get is pretty blatant, if not downright automated spam, and that gets zapped pretty quickly. There is some that falls into a grey area, and we've treated that on a case-by-case basis. If you have a question about something you see, hit "Notify" and we'll look at it. If you have a question about something you want to post that might be interpreted as advertising, then PM Packlite.
OK, personal question: Are you writing a book? If so, I'd love to read it!