Is it possible to share prototypes privately?
afaik, the share feature doesn't have that option but i'd be really stoked if that made it's way into a future release
yes, with your own hosting service. :) i do it through AWS, but of course, you'll need to front with your own security. The good part however, is that you can quickly create an instance and destroy it, if you use AMIs (i.e. create an image with your hosting bits on it)
I'd guess Dropbox works too