You can use Repute objects to give karma to the users, also remember that there is denormalized data of the total karma on the user objects called .reputation.
There is no convenience API for this at the moment, but as long as you create a valid Repute and update user's .reputation record, you can modify karma in other situations.
You can use Repute objects - corresponding to the instance of adding/removing reputation to/from the account - to give karma to the users, also users. Also remember that there is denormalized data of the total karma on the user objects called .reputation.
There is no convenience API for this at the moment, but as long as you create a valid Repute and update user's .reputation record, you can modify karma in other situations.
There is direct (but optional) link between the Repute and the Post object for which reputation was given. In order to link the repute for any type object, we'd need a generic relation instead of a ForeignKey.