Every Beaker user has a hyperdrive that represents them publicly. This is the "Profile Drive." It is created during the initial setup.
You can find your profile drive by looking at the top right of the browser. You will find your profile picture. You can click on it to open your profile drive.
To change your name, bio, or picture, see Changing a Drive's Title or Thumbnail.
Some applications will use your profile to save and publish content. (This is how the Microblog Feed Template works.) When they want to use your profile, you will be prompted with this interface:
You can choose your profile to grant read access. Any additional permissions will be requested.
See also: the beaker.contacts API.