A couple of points. First, I am confident that purchasing an ad in B&W does, in now way, affect whether or not a photographer will be published in the magazine. First, the quarter-page ads, which are the most abundant, are too cheap to have any monetary influence. Second, the magazine publishes so many different photographers from their two annual contest issues as well as throughout the year, that there is bound to be some overlap between publishing and advertising. I don't think that rates as a perception of impropriety. Lastly, at least on this subject, I was published in B&W a couple of years ago (straight landscape!)and seriously considered purchasing a small ad to keep my name in front of people's faces. I didn't do it, but can definitely see others going that route. That might be were much of the overlap lies.
As for galleries, Rob's and Russ' experiences are similar to mine. As I shoot straight b/w landscapes, which is the antithesis to today's post-modern
psuedo-photography, my work is not in high demand. Still, I have managed to get a large museum exhibit this past summer and a few gallery commitments for 2010-2011. What I found helps, considerably, is an introduction, be it by mail, email or phone. The art world is very cliquish. If a gallery owner/director thinks others in power positions appreciate the value of your work, you'll have a better chance.
And Russ, I tried doing the "take a look at my website" thing, but it fell on deaf ears every, single time. Not sure the art gallery world is ready for that, yet.