This paper analyzes the discourse of two English-language discussion forums with different themes – weight management and dogs – in order to demonstrate how pragmatic functions (e.g., greeting, providing encouragement, requesting information, scolding) can be expressed by a range of linguistic structures. The analysis is theoretically grounded in Lave and Wenger’s (1991) view that learning should ideally be socioculturally situated within a Community of Practice (CoP). As such, the concept of the traditional (i.e., offline) CoP is contrasted with the hierarchy, norms, rules, and structures that exist in online communities. This type of contrast is vital to an understanding of online vs. offline social and cultural practices since some of the constructs (e.g., gatekeeping, explicit vs. implicit socialization) are fundamentally different. This paper thus draws attention to the importance of considering participation and socialization of L2 learners in authentic contexts consistent within recent broad-based theoretical and empirical discussions in SLA (Hall, Cheng, & Carlson, 2006; Kasper, 2001; Kramsch, & Whiteside, 2007; Lafford, 2007; Swain & Deters, 2007). Findings show that CoPs can indeed be created online. Moreover, message boards are effective tools for language teachers and language learners.