If the internet was (somehow) working we could all meet in the Midwest and start a decent sized city (I don't know about the forumers across the ocean)
the lower the ID the more power you had
the city-state would be a democratic oligarchy with the very few 3-didgets left being on the council
the few dozen 4-didgets would be given the power to rule over certain districts of the city
all the 5-didgets would be of a more powerless class with many sub-classes
10k - wealthy noble/could own slaves
20k - upper-middle class/head-slave overseers/military captains
30k - standard-middle class/slave overseers/military(?)
40k - lower-middle class/worked physical jobs/military
50k+ - 3rd class/farmer peasants/militia In times of need
once you got into the 6-didgets that would make up the many slaves of the city-state who would work the farms and mines