Nothing nor nobody said you couldn’t talk about it on your forum.
Come on. You cannot be serious, here.
Google does it for example. You can access pretty much all their services with service.google.com
It is true you can use google.com/finance instead of finance.google.com for example. It never confused me personally (I don’t see how it could). I see it as an additional option and don’t really see any bad side to it (confusion, or other). We have different opinions on the matter, I guess.
I would argue it’s just a little better. 2 slashs and a letter less to enter on your keyboard if you’re entering it manually and far easier to remember for people who may not easily remember a /c/ first has to be typed in before the category name. (Ok you have to enter a point with the other method, so only 1 slash more, counts)
Personally, and I will conclude with this: I do use this kind of subdomain things for google or other sites (which I usually enter manually as I don’t have bookmarks of things I don’t use regularly). I don’t know, I guess it just “suits” me and I like it better than domain.xxx/service. I get the point it’s 'the same" and it’s “no better”.
Fortunately, I’m free to do it, and you’re free to NOT do it. Everything is well.