Every Facebook user has an identifier, for instance 73209645 or 1000002894239.
Identifiers are given incrementally to newly created accounts.
Some users even boast about their low number of digits. Typically, anyone below 100 is a classmate of Facebook's creator, and anyone below 10000 studied at Harvard.
QUESTION: Is there a mapping of identifiers and account creation dates?
100030000 < id < 100030000 : Account created between 20080411 and 20080412 100040000 < id < 100050000 : Account created between 20080412 and 20080414 [...]