Adjusting your site to work with Organic Groups
Now that we have installed OG, we need to make some configuration changes to use the group functionality effectively. As we make this shift, it will help if we adjust our perspective to think about the content differently. Before we installed OG, content was created within the site and generally displayed via a view or a menu. Now, with OG installed, content is obviously still posted within the site, but it can also be contained within one or more groups.
In the Drupal 6 version of OG, groups were created by creating nodes of designated content types. In the Drupal 7 version, groups can be created using any entity.
Note
Entities are chunks of content in Drupal 7. Nodes, users, and taxonomy terms are all entities. Bundles are implementations of entity types. For example, the content types are bundles of node entity types. You can learn more about these terms (and many other Drupal terms) at http://drupal.org/glossary.
Since it is still possible...