Settings
Name and handle
Optional, and seen by nobody else. It is for resetting a forgotten password by mail once this instance sends mail; until then the owner can send you a reset link.
Bio
A line about yourself. Everybody sees it, including people you do not know.
What you rate
Turning one off hides it from your navigation and from your profile. Nothing is deleted — turn it back on and every rating is where you left it.
Languages you read books in
The book search leaves out books with no edition in any of these. None ticked means every language.
Who sees what
There is one relationship: following. Two people who follow each other are friends, and a friend can be put on your close list — they are never told. Somebody who follows without being followed back sees what everyone sees, which is why there is no separate setting for them.
Or one thing at a time. Changing a row below makes it a mix of your own.