The Blacklist is a list of Jarls (including your clanmates), with whom you would like to restrict communication for some reason.

Blocked users will not be able to send you personal messages, and their messages in chats will be hidden.

If you remove a user from the Blacklist, you will start receiving messages from this user and will see their messages in chats.

To block a Jarl, hit the Jarl's name in a chat, select the "To the Blacklist" icon in the window that appears, and confirm your action.

You can also add a Jarl to the Blacklist from Mail. To do that, select the Jarl's message in the message list, hit the Jarl's userpic, and then the "Block" button in the window that appears.

To remove a player from your Blacklist, open the Blacklist section in the Menu, then select one or several Jarls by checking the boxes next to their userpics, and hit the "Unblock" button at the bottom of the screen.