Lumen (formerly Chilling Effects Clearinghouse)

Lumen is an independent research project studying cease and desist letters concerning online content. We collect and analyze requests to remove material from the web. Their goals are to facilitate research about the different kinds of complaints and requests for removal–both legitimate and questionable–that are being sent to Internet publishers, search engines, and service providers, and to provide as much transparency as possible about the “ecology” of such notices, in terms of who is sending them and why, and to what effect.

The Lumen database contains millions of notices, many of them with a valid legal basis, some of them without, and some on the murky border.