Activity Feed: Failures and Operations

The activity feed makes three promises. An activity that the community accepts is never lost. While the system is healthy, 99 percent of new activities appear in followers' feeds within 60 seconds. A removed post disappears from feeds within the same 60 seconds.

It also declines to make three promises. During an incident, it promises only that feeds are at most 15 minutes old, and it may leave stars out of them entirely. It does not promise that activities from different sources appear in the exact order they were published. And it does not promise a complete feed while a rebuild is running