My understanding is Heroku is primarily a development environment. If you want to make a full-blown gajillion-user app, you'll probably have to move it off Hero

My understanding is Heroku is primarily a development environment. If you want to make a full-blown gajillion-user app, you'll probably have to move it off Heroku's servers -- i.e. I don't see any way to edit DNS entries / use your own URL. Maybe they'll allow you to update your account if you want to use them for hosting.