uses for mongodb ObjectId creation time

Question

The ObjectId used as the default key in mongodb documents has embedded timestamp (calling objectid.generation_time returns a datetime object). So it is possible

Answer 1

From: http://www.mongodb.org/display/DOCS/Object+IDs#ObjectIDs-DocumentTimestamps

"sorting on an _id field that stores ObjectId values is roughly equivalent to sorting by creation time, although this relationship is not strict with ObjectId values generated on multiple systems within a single second."