In the rule “Categories”, after the text “a Storyteller may add one entry, which must consist of a Name and Description, to a Category.” add the following text:

When a Storyteller does so, they gain Points according to the formula P = S - N, where P is the number of Points gained by that Storyteller if P is greater than 0, S is the number of Storytellers (not counting the Publisher), and N is the number of entries in that Category before that Storyteller added a new entry. If P is 0 or less, no Points are gained by that Storyteller for this action..