Motoyama, Marti, et al. "An analysis of underground forums." Proceedings of the 2011 ACM SIGCOMM conference on Internet measurement conference. 2011.

This paper investigates underground forums, a type of online social network (OSN) where participants discuss abusive tactics and trade illegal goods and services. Unlike traditional OSNs like Facebook, these forums reflect dynamic trust relationships among participants who are generally distrustful of one another. The study empirically characterizes six forums: BlackHatWorld, Carders, HackSector, HackE1ite, Freehack, and L33tCrew. It examines the social network structures, the nature of transactions, and the mechanisms of trust formation and dissolution within these communities.