The idea is to have "walls" to post questions, anouncements, etc. in a non-public facing section of an ArcGIS subscription account. This would look similar to other social networking sites. There could be additional "walls" in the landing pages for each group that gets created. So, only people who are members of the organization can read and post on the main wall. Only members of a particular group can post to that group's wall.
Content already has the ability to be rated and commented on, which is very useful. This would be the next logical evolution.