May I ask are there any ways for users to categorize their favorites by self-written tags (not the official tags provided)?
E.g. in Biology Stack Exchange, a user is asking a question with the tag 'respiratory system', but the answer given involves something related to biochemistry, which I really like, but the user didn't tag it in his/her question. If I want to create my own tag for my own categorization purpose of favorites, how can I do it?