What does "going, going, gone" mean?

No longer available, as in If you want this last doughnut speak up—going, going, gone! This expression, used by auctioneers to indicate the acceptance of a final bid for an item, is occasionally used more loosely, as in the example. It is beloved by baseball announcers when describing a home run as it approaches and clears the outfield wall. [c. 1800]