Creating a Private Online Group or Community
Looking for a way to share content, photos, videos, and more with a select group of people? Create a private Posterous site. A private site functions just like a regular Posterous site, except that only authorized people can access it. For example, you could create a private community for a workgroup, an organization, or even your family.
To make a site private, go to its Settings page to edit your privacy settings. Here you can password-protect your site and then add the people with whom you want to collaborate as contributors. Only those with the password can access your site, and only designated contributors can post.