I think it's a good idea and I can push to get our program advertised in your guide.
A couple of reasons you are not getting calls about it.
1) The guide itself is not well advertised. Well, we know you and the
C++ book you have but only a fraction of us know about your guide via QN, GD or WM forum.
2) It's a free guide and you should post it wherever you can. Instead, you have it somewhere on your site. The last time I went there, it took me a while to figure out where the guide is. I don't know the current status of your website but I believe a prominent display will help.
3) How much does it cost to advertise on your guide. You don't update the guide frequently so it's not like people will get your guide weekly. From advertiser's point of view, it's a very static and narrow audience to target.
These are my constructive input. I'm in the same position who tries to get advertisers on this website and those are my findings of which works and not.
Hope it helps.
PS: Send me a PM about the advertising cost when you decide to do that.
