WireframeApp allows you to quickly share your project designs publicly, or privately where you can leave comments and get feedback easily.
Once you're signed in, you can share your work with anyone you like. Simply click on the Collaborators icon, and then input their email address to add collaborators.
Projects will be shared as public by default, which means that they can be viewed by anyone with the link.
You can manually set your project as private under Settings → Overall Project → Public Visibility, but account access limits the number of private projects an account can have; with Enterprise Account you can create unlimited private projects.
If you ever want to manage more than one WireframeApp accounts at any time, click on the WireframeApp logo on the top-left corner of the page, and click on the switch / manage button. Here you will be able to quickly switch between accounts - along with the ability to assign more admin users or rename accounts if you wish.