Yeah, Dustin Moskovitz's concise explanation: "1-3 were accounts used to test registration. Evidently it only took Mark 3 tries to clear the bugs." Source: htt

Yeah, Dustin Moskovitz's concise explanation: "1-3 were accounts used to test registration. Evidently it only took Mark 3 tries to clear the bugs." Source: https://www.quora.com/Facebook-Company-History/The-first-user-id-on-Facebook-is-4-Mark-Zuckerberg-Who-was-1%E2%80%933?share=1 https://www.quora.com/Facebook-Company-History/The-first-use...