The Blacklist and Whitelist features help us show results that are customised by you.
Whitelist is a list that you create, of users that you do not want to unfollow. These could be celebrities, close friends, perhaps even your family. When you add an account to your Whitelist, we will never suggest that you unfollow them, even if they do not follow you back. (Although you might want to have a little word with Mom about why she isn’t following you back.)
On the other hand, when you never want to follow a user, you could add him to your Blacklist. This way, we won’t ever suggest you follow them, even if they follow you. You can keep your feed clean of spammers, fake accounts, and your sworn nemesis.