The Karma system is very simple: You can 'like' or 'dislike' a comment or post by selecting so. For every 'like' a person receives they will gain (internal) points which will help them gain ranks. You also get a small amount of these points yourself  just by 'liking' or 'disliking' others(Although it is small). We decided to have a karma system like this, in order to encourage more people to give feedback to others. Furthermore, the 'likes' or 'dislikes' that a post receives are instantly viewable to everyone.