1. A method of providing selective notifications to clients, the method comprising: identifying, using a notification system, one or more tracked categories resident in an end user document, the tracked category representing a portion of existing textual content of the document residing within the document; identifying a change in one or more of the tracked categories of the document by monitoring activity regarding the portion of existing textual content; identifying a client to notify of the change in the tracked category; and sending a notification to a client, the notification providing notice that a change has occurred in a tracked category of the document, wherein a client establishes a subscription to receive updates when a tracked category changes, the subscription being established by identifying portions of a document while the document is being edited.