From a suggestion on the SL researchers list
Science 27 July 2007:
Online here.
Vol. 317. no. 5837, pp. 472 – 476
DOI: 10.1126/science.1146930
Author: William Sims Bainbridge
Quote from the abstract:
“This article uses Second Life and World of Warcraft as two very different examples of current virtual worlds that foreshadow future developments, introducing a number of research methodologies that scientists are now exploring, including formal experimentation, observational ethnography, and quantitative analysis of economic markets or social networks.”