RT Journal Article T1 An analysis of fake social media engagement services A1 Nevado Catalán, David A1 Pastrana Portillo, Sergio A1 Vallina-Rodriguez, Narseo A1 Estévez Tapiador, Juan Manuel AB Fake engagement services allow users of online social media and other web platforms to illegitimately increase their online reach and boost their perceived popularity. Driven by socio-economic and even political motivations, the demand for fake engagement services has increased in the last years, which has incentivized the rise of a vast underground market and support infrastructure. Prior research in this area has been limited to the study of the infrastructure used to provide these services (e.g., botnets) and to the development of algorithms to detect and remove fake activity in online targeted platforms. Yet, the platforms in which these services are sold (known as panels) and the underground markets offering these services have not received much research attention. To fill this knowledge gap, this paper studies Social Media Management (SMM) panels, i.e., reselling platforms¿often found in underground forums¿in which a large variety of fake engagement services are offered. By daily crawling 86 representative SMM panels for 4 months, we harvest a dataset with 2.8 M forum entries grouped into 61k different services. This dataset allows us to build a detailed catalog of the services for sale, the platforms they target, and to derive new insights on fake social engagement services and its market. We then perform an economic analysis of fake engagement services and their trading activities by automatically analyzing 7k threads in underground forums. Our analysis reveals a broad range of offered services and levels of customization, where buyers can acquire fake engagement services by selecting features such as the quality of the service, the speed of delivery, the country of origin, and even personal attributes of the fake account (e.g., gender). The price analysis also yields interesting empirical results, showing significant disparities between prices of the same product across different markets. These observations suggest that the market is still undeveloped and sellers do not know the real market value of the services that they offer, leading them to underprice or overprice their services. PB Elsevier YR 2023 FD 2023-01-01 LK https://hdl.handle.net/10016/37486 UL https://hdl.handle.net/10016/37486 LA eng NO This work was supported by the EU Horizon 2020 Research and Innovation Program under Grant agreement no. 101021377 (TRUST aWARE ); the Spanish grants ODIO (PID2019-111429RB-C21 and PID2019-111429RB-C22), and the Region of Madrid grant CYNAMON-CM (P2018/TCS-4566), co-financed by European Structural Funds ESF and FEDER. DS e-Archivo RD 1 sept. 2024