TER study: 1.4M sexual contact links reveal global network with small-world properties

A new preprint on arXiv (arxiv:2607.21972) by Ito, Shigeta, Asakura, and Morita presents the first large-scale, cross-country analysis of a sexual contact network derived from a commercial-sex review platform. The team scraped 1,436,738 client-sex worker links from The Erotic Review (TER), covering reviews posted between 1999 and 2024 in 97 countries and territories. The resulting bipartite network exhibited small-world properties: a giant connected component, short average path lengths (typical of social networks), high bipartite clustering, and disassortative degree correlations—meaning highly connected clients tended to link to less connected sex workers and vice versa.

Despite most reviews being concentrated in the United States, a small minority of clients reviewed sex workers in multiple countries, creating spatial bridges that connected otherwise distant regions. Long-term users (spanning many years) acted as temporal bridges, making the aggregated network significantly more compact than networks built from shorter time windows. Contacts involving transgender female sex workers were structurally concentrated: clients who reviewed both cisgender and transgender female sex workers were a small minority but accounted for a large proportion of transgender-related reviews, and those clients showed higher cross-country activity. The findings demonstrate how digital trace data—despite its ethical and privacy constraints—can reveal hidden large-scale contact structures relevant for modeling sexually transmitted infection (STI) spread.