It's possible to get the registration times for these accounts from the Digg API. I did that and they were registered in large blocks starting 10/16/2010 10:03:05 and ending 10/17/2010 13:37:59.
The blocks (ordered by the registration time) have registrations averaging a few minutes apart with hours between blocks. IMHO these could easily have been generated manually.
The blocks (ordered by the registration time) have registrations averaging a few minutes apart with hours between blocks. IMHO these could easily have been generated manually.
These blocks do not overlap, although the ddXX block was done in two tranches.