I poked around the data a bit (I uploaded a JSON file below). First, I separated the tweets into two sets based on the last eight hex digits (00s and 50s). In each set, I parsed each 16-digit message as an integer, converted that to a binary string, and reversed the binary digits. Parsing that as an integer again gives numbers that roughly increase over time.

Here is a chart of the 00s (plotted against tweet number):

http://i48.tinypic.com/svl4jm.png

and of the 50s:

http://i46.tinypic.com/2mn1wg7.png

It's rather strange that the data isn't perfectly monotonic.

I'll look into the tweet coordinates next.