slackroll is a package or upgrade manager for Slackware Linux. It is designed to work with official mirrors in systems mainly composed of official packages with a few unofficial packages. It lets you automatically upgrade or install packages, and displays which packages have been added or removed from the Slackware tree.
BitTorrent is a tool for copying files from one machine to another. FTP punishes sites for being popular. Since all uploading is done from one place, a popular site needs big iron and big bandwidth. With BitTorrent, clients automatically mirror files they download, making the publisher's burden almost nothing.
Releaser is a set of scripts to automate and manage the tasks related to software package releases. It is designed to be modular and to make it easy to both select a particular set of actions associated with releases of a particular project (such as changelog generation, uploading of tarballs, posting announcements to mailing lists), and create new actions that integrate seamlessly into the process. Its status is still somewhat experimental, but the most basic functionality is there.
pmq is a tool to query installed Perl modules. It will find the .pm file for a given module (like which(1) for Perl) and its version number. It is robust against modules that give an error on loading or don't define a version number. pmq --all lists information on all installed modules, which is useful for checking that Perl upgrades haven't broken anything.