Meetings
Meetings are very effective to build consensus, make a decision, or resolve conflicts. They are ineffective for information dissemination or one-way communication.
That's why we are mindful about when we choose to organize a meeting, because every meeting carries a cost in terms of the disruption it causes to team members' work schedule.
Every meeting has an agenda and is driving toward an outcome. Without agenda or outcome, we don't hold a meeting but write a document instead. Only people expected to participate are invited to a meeting. Everybody else gets the meeting minutes and conclusion as a document afterwards.