The ability to argue well is a valuable skill for students in both formal and informal learning environments. While many studies have explored the argumentative practices in formal environments and some researchers have developed tools to enhance the argumentative skills, the social argumentation that is occurring in informal spaces has yet to be broadly investigated. The challenges associated with observing and capturing the interactions in authentic settings can be identified as the main reasons for this deficiency. On the other hand, the advancements in information technologies and the way these improvements lift the barriers between school and afterschool settings present ways to eliminate these challenges. To this end, this study utilizes a popular Massively Multiplayer Online Role-Playing Game (MMORPG), World of Warcraft (WoW), which provides an authentic environment, to investigate the quality of argumentation in online synchronous communication without interfering with the substantial characteristics of the interaction. The results of the study demonstrate the quality of argumentation skills that a group of adolescents are displaying in online synchronous WoW chat as well as the patterns that emerge from the interplay between a number of contextual variables including synchronicity, interest, and authenticity.