Newsletters Are New Scientific Gatekeepers

A multi‑year scrape of Substack (47,562 public science posts from 2,785 newsletters) shows that independent newsletters concentrate attention, surface research, and form durable elites that disproportionately shape which papers, people, and questions enter public conversation. The platform's recommendation graph and leaderboard dynamics produce a small, stable set of highly visible writers and topics, even as overall volume grows. — If newsletters become de facto gatekeepers of science, they change citation patterns, public understanding of research, and who gets the power to frame scientific controversies — with implications for trust, funding narratives and policy influence.