This is all just an over-engineered way of saying: "If a person's lifetime tally of all unique fans (say: 150 different people, cumulative) consistently matche

This is all just an over-engineered way of saying: "If a person's lifetime tally of all unique fans (say: 150 different people, cumulative) consistently matches the typical number of unique fans per thread/article (say: ~135 on any particular post) then those fans are probably employees with vested interests" (in other words, it's the same people upvoting that guy every time, and they're all in a gang) You don't need big O notation and hash tables to conflate that idea. See: https://en.wikipedia.org/wiki/HyperLogLog https://en.wikipedia.org/wiki/HyperLogLog And: https://en.wikipedia.org/wiki/Cardinality https://en.wikipedia.org/wiki/Cardinality