Actually, a bit of both.
The most public I get is through this blog (which just passed 750-thousand views), but the feedback I get from the blog isn't necessarily huge, except from my few regulars... thanks team.
As I said in the previous response, and as I often repeat, I often feel like I'm riding a zeitgeist... drawing on the same influences as many of the designers around me, which often leads to similar outputs. If I were to design completely privately until things were ready to show, I'm just a single person working to a goal, so design teams will inevitably beat me to the punch...and specialists in those teams will ensure good production values, and good exposure. So my work, even if I start earlier will often appear too late and might look like an inferior copy.
I'd rather design publicly so at least I can point to the progress before someone else's product comes out. I have no fear of people "stealing my work", in fact I'm basically resigned to that after having "freelance artists" claim credit for my illustrations, and numerous game ideas spontaneously appearing in other designs as I'm similarly working on my own.
It's frustrating...but it's a hobby, and I love doing it. I'm just glad my life doesn't depend on it.