Methods and systems are provided for real-time blocking of content from an organization activity timeline of an organization. The content blocked can be, for example, activities, or contributions to those activities. The organization activity timeline is displayed within a user interface to show activities involving a particular external contact and one or more users of the organization. The disclosed methods and systems can be used to control which activities or contributions to activities are displayed in the organization activity timeline. One or more identifiers can be added to one or more blacklists. New activities are evaluated for inclusion in the organization activity timeline. Any new activity that includes an identifier (or contributions to that new activity) can be blocked so that it does not appear in the organization activity timeline.