As projects grow, so does the amount of work getting done, and soon it becomes harder to know about all the work that matters to you. With Herald you can to build conditional rules that match objects throughout the Phabricator system to keep track of what's important. For example, you can build a rule that watches for diffs against the code you own, then add yourself a reviewer, or get CC'd, or add a whole team as a reviewer with Projects.
Global Rules help keep process in place and followed. Set up rules for manditory code reviewers, block certain commits from landing in the repo, or simply trigger audits. These rules help reduce mistakes and ensure more coverage is placed where you need it most.