This document studies avatar personalization across three virtual worlds: World of Warcraft, Maple Story, and Second Life. It finds that WoW players are on average older (29.8 years) than Maple Story (18.1 years) and have more alternate characters, while Second Life players are oldest on average (41.1 years) and have fewer alternate characters. The document also examines differences in how users customize their avatars across domains and the relationship between avatar customization and user identity.