Does DataSift deliver the historic post data in oldest to newest order of each post’s creation timestamp?
No - there is no guarantee to the order in which you will receive your historics data. Your Historics query will be split into day-long "chunks", and these chunks may be processed in any order. The same is also true with 'live-streaming' via both Push and the Streaming API - we can not guanantee your interactions will be delivered in the order in which they were created.
Thank you for the information, Jason.