This paper reports the results of a controlled field experiment in which voice communication was introduced into an existing online community (online gaming guilds within the popular game "World of Warcraft"), comparing a mix of voice and text with text only. Quantitative results suggest increases in liking and trust due to the addition of voice, as well as insulation from unexpected negative impacts of text-only play. The findings are discussed with respect to social capital, cyberbalkanization, and the general computer-mediated communication literature, with special attention paid to social information processing theory.