An interesting paper in the newest edition of Annual Review of Psychology titled "Conceptual Consumption" by Dan Ariely and Michael Norton:
The paper examines what goods we "consume", and how we choose between different goods (conceptual vs. physical). One interesting identification is of social utility with conceptual utility, and how these ideas may be applied to virtual worlds.
Citing Schelling (1984) as one motivation for describing the mind as a "consuming organ" the paper explores such interesting questions as "mental simulation of events, past and future" when deciding to eat a cookie. A very interesting read!