> the new SSNs - unique identifiers that never change and connect you across services And just like SSNs both the "unique" and the "never change" are only true

> the new SSNs - unique identifiers that never change and connect you across services And just like SSNs both the "unique" and the "never change" are only true of the spherical cow version of the system. Phone numbers are actually substantially worse at being unique and unchanging, what with people in families sharing a phone or trading phone numbers, people forgetting to transfer the number when switching carriers, people intentionally switching numbers in an attempt to end spam calls... The number of ways to break the assumed invariants is actually quite high. See Falsehoods Programmers Believe About Phone Numbers [0]. [0] https://github.com/google/libphonenumber/blob/master/FALSEHOODS.md https://github.com/google/libphonenumber/blob/master/FALSEHO...