Some digital document libraries have a notification service that informs subscribers of newly available documents. The notification service for a software repository is somewhat different, because it informs subscribers of changes and bug fixes to the software as much or more than of additions of new software. In the early days of the Netlib repository, when all access was by email and the traffic was mostly from professional numerical analysts, we relied on log files to send out notification of important bug fixes to everyone who had retrieved affected files. Now, because access is more anonymous and a wider spectrum of users are involved, the old scheme has been replaced by explicit subscription. People may indicate interest in specific Netlib directories, using subscribe and unsubscribe commands. Automatic notification is sent, on a daily basis, when files in the directory are changed. The subscriber lists also give the authors and editors a way to judge what community is particularly interested in a given Netlib collection.