The Insidious Big Brother Database (BBDB) is a contact management utility created by Jamie Zawinski for use with Emacs. It is tightly integrated with several mail and news readers (see below), allowing it to create database entries directly from mail and news messages. As is usual with applications for Emacs, this record creation can be configured in many ways, ranging from a boolean create/don't create setting to creation based on the result of a user-supplied function.

Database records can be used to store many types of information, from name and address to URLs and X-Face images. This information can be displayed when a message from an entity named in a database record is recieved. In addition, messages from database members can be tagged in the Gnus Summary Buffer, and Gnus scoring can be configured based on the contents of database records. Supercite citations can even be preset through the use of records in the BBDB