Robert, thanks for looking over the Article Submission Guidelines (ASG) document so closely. I am sure it needs more fine-tuning and questions such as yours will help make it and the upcoming style guide better. I have edited both references to headlines in that document as being under review/discussion until we decide how to treat them.
That part of the ASG was borrowed with permission from FlyingSolo
, who publish an online magazine among other things. Dex Randall secured their permission and also created the initial draft of the ASG.
I agree that capitalizing all words (or at least most words) in headlines is widespread (including as you point out on the Community site which carries a lot of weight IMHO), but I think that not capitalizing all words in titles is also an accepted practice. For example in addition to FlyingSolo, my local newspaper the Denver Post only capitalizes the first word of a title (unless there's a proper noun, etc in the title).
So I think how we treat capitalization in headlines for the magazine is ultimately is up to us, with some of the main criteria being: * Consistency
-Once we decide on a style rule we should be consistent with it. I don't think the magazine has to follow the capitalization style on the Community site, but it is definitely a precedent to consider (also in line with the next "simplicity" point). * Simplicity
-What will be easiest in this community project with lots of authors? If we can avoid extra work for editors that's a good thing. If capitalizing most words in titles is seen as more common we can definitely follow that convention. * Style
-What kind of look/image do we want for the magazine? Here's where I think non-capitalization is a better fit for the magazine's style. I think capitalizing all words in headlines is more formal/traditional than not capitalizing.
So that's how I see this point, I hope that helps clarify your good question about capitalization for headlines in the magazine. What do you (and other team members) think we should do? Nothing's written in stone here so let's think it through some more and figure out how we want to handle this.