  Over the past few years, many black-hat marketplaces have emerged that
facilitate access to reputation manipulation services such as fake Facebook
likes, fraudulent search engine optimization (SEO), or bogus Amazon reviews. In
order to deploy effective technical and legal countermeasures, it is important
to understand how these black-hat marketplaces operate, shedding light on the
services they offer, who is selling, who is buying, what are they buying, who
is more successful, why are they successful, etc. Toward this goal, in this
paper, we present a detailed micro-economic analysis of a popular online
black-hat marketplace, namely, SEOClerks.com. As the site provides
non-anonymized transaction information, we set to analyze selling and buying
behavior of individual users, propose a strategy to identify key users, and
study their tactics as compared to other (non-key) users. We find that key
users: (1) are mostly located in Asian countries, (2) are focused more on
selling black-hat SEO services, (3) tend to list more lower priced services,
and (4) sometimes buy services from other sellers and then sell at higher
prices. Finally, we discuss the implications of our analysis with respect to
devising effective economic and legal intervention strategies against
marketplace operators and key users.
