Lumen

Lumen is a research project at the Harvard Law School Library studying takedown notices along with other legal removal requests and demands concerning online content. It collects and analyzes requests to remove material from the web. Its aim is to facilitate research about the complaints and requests for removal sent to Internet publishers, search engines, and service providers.

Lumen was founded in 2002 by then-Berkman Klein Center Fellow Wendy Seltzer. It was housed at and supported by Harvard's Berkman Klein Center until 2025. It is based at Harvard Law School Library in Cambridge, Massachusetts.

Its database now includes complaints of all varieties, including trademark, defamation, and privacy, domestic and international, and court orders. Companies such as Google, Twitter, YouTube, Wikipedia, Meta, Medium, Vimeo, Cloudflare, and Wordpress provide voluntary submissions. As of June 2026, the project hosts over seventy-five million notices, referencing over ten billion URLs.