As You know Sphere.Social allows to use iframes. For instance, You may add Your own blog's feed into Your publication. Here is my Tumbler blog under a password. To view its content You must use the password: 'dvj-sphere-social-blog'. The page of authentification: https://www.tumblr.com/blog_auth/dvj-sphere-social-blog. An embedding of the password protected user blogs containg sufficient actual information about them allows to combine privacy in social networks with transparency. It is a very important feature.