Reputation is personalized and represents how much you can trust a Memo account from the perspective of your own account. Reputation is calculated by taking the number of people you follow who follow the account minus the number of people you follow who muted the account divided by the total number of people you are following.
(number of people you follow who follow the account -
number of people you follow who muted the account) /
(total number of people you follow)
Red indicates a reputation of less than 0%, Grey is between 0% and 2.5%, Yellow is between 2.5% and 10%, Green is greater than 10%, and Blue with a star means you directly follow that user.