As a victim of harassment, I want to be able to restrict who can send me pings -- both specific users and all users below a given permission level. See https://meta.wikimedia.org/wiki/2016_Community_Wishlist_Survey/Categories/Miscellaneous#Allow_users_to_restrict_who_can_send_them_email (T138166: Allow users to restrict who can send them direct emails via Special:EmailUser) and https://meta.wikimedia.org/wiki/2016_Community_Wishlist_Survey/Categories/Miscellaneous#Allow_users_to_restrict_who_can_send_them_notifications.
URL: https://meta.wikimedia.org/wiki/Community_health_initiative/Notifications_blacklist