volatile.debian.net - "Some packages aim at fast moving targets like spam filtering and virus scanning, and even via using updated virus patterns, this doesn't really work for the full time of a stable release. The main issue of volatile is to allow system administrators to update their systems in a nice, consistent way without getting the drawbacks of using unstable, even without getting the drawback for the selected packages."
Whitelist -- Debian Mailing Lists - "This is a special pseudo-mailing list to which people can subscribe to prove they are not spammers.This allows one to avoid the restrictions imposed on non-subscriber posts to other mailing lists, in particular the mailing lists that allow posts only from subscribers. "
