It has been observed that physical attributes serve as a guide to participants in their address form choices, when meeting someone for the first time (Clyne, Norrby & Warren 2009). In many online contexts, however, participants interact with virtual identities and have no access to information on their interlocutor’s age, sex or socioeconomic background. Which pronominal and nominal forms, if any, do they employ in such environments? And what functions do they serve? These are questions addressed in this paper in the context of anonymous interactions between buyers and sellers in e-service encounters in Mercado Libre (ML), an online market place. The perspective adopted is that of variational pragmatics (Schneider & Barron 2008), with a focus on regional variation (Schneider & Placencia 2017) on the basis of the analysis of address usage in two corpora extracted from two subsidiaries of ML: ML-Ecuador and ML-Mexico. With globalization, technological developments and the expansion of social networking sites, it would not be unreasonable to expect that behaviours such as addressing are becoming more uniform (see Sifianou 2013). Indeed, the results of the present study, based on 1342 posts, suggest that there is a move in both contexts towards informality in address behaviour; however, this apparent trend is more pronounced in the Mexican corpus, with, for example, a higher incidence of T pronominal address and the absence of formal nominal forms. In the Ecuadorian corpus, on the other hand, informal pronominal address has a relatively high incidence; however, V address still has a slightly higher incidence. Also, formal nominal address, while not being predominant, can still be found in the Ecuadorian corpus. Finally, possible functions of address forms are discussed in relation to the types of acts they co-occur with. The study draws on works on address forms, service encounters, politeness and CMDA.