A FAN may customize their personal page, select and display Favorites (Contributors and Submissions), participate in Forum discussions, and message others on the site.
A CONTRIBUTOR shares these permissions and additionally may create Submissions.
A GROUP ADMINISTRATOR is the Administrator of a group of Contributors and/or Projects. See more about Groups here. You may combine Group Administrator role with Fan or Contributor role, knowing that your Submissions, Favorites, etc. will be connected with the Group. (You may want to create separate accounts with different email addresses.)