Rules can be a confusing topic. Exchange owns and maintains one set of rules, and Outlook owns another set. The rules feature exposed in Outlook could be considered a superset of Exchange rules because the Outlook Rules Editor has traditionally been superior to and more functional than the version supplied with Exchange for use with Outlook Web App. However, the superiority only really exists in terms of the user interface to rules. Behind the scenes, Exchange performs the majority of the processing on incoming items and leaves Outlook to perform only the steps that have to be executed on a client.