The email used while signing up for 'Emotions for HN' is not stored on the sever, instead a one-way hash of the email is stored to identify the user. All the information transmitted from the plugin to server has this hashed value to uniquely identify the user. This hash value is also used to prevent double voting by the same user. This plugin collects user votes per comment and those votes stored on the server.

Plugin doesn't use any third party and never sends any collected data to any third party.