To discuss an entity, it is possible to comment on the entity. The discussion can be opened at the bottom of the entity view.
It is possible to reply to an existing discussion by clicking Reply on the wanted comment. When hovering above a comment, it is possible to like (thumbs up) the comment and watch the discussion (eye), or delete (bin) or edit (pencil) the comment if it is yours.
There can also be multiple discussions on an entity. A new discussion can be started by clicking New Discussion.