BuddyPress.org

I am quite new to both WP and BP. I have read codex from WP and BP on roles and responsibilities. Documentation goes into great length to provide differences amongst the various roles; however, I have concluded (after testing) that there is really only two roles: Admin and everything else. That meant subscribers, contributor, authors, and members all have the same capabilities —- which are create groups, create topics, post to group forums, as well as post to sitewide forums. Am I correct?

Please confirm. I am creating a WP/BP site as part of my graduate work project.