"12 people are viewing this" is almost always a random number on a timer. Where it is not backed by real data it is a deceptive commercial practice, and it reads as one to experienced buyers either way.
Impact is importance multiplied by the confidence tier’s weight — SPECIFICATION 1.0, RESEARCH 0.7, EMERGING 0.3, EXPERIMENTAL 0.1. Two rules backed by the same class of evidence therefore always carry the same weight, which is what makes the score reproducible rather than hand-tuned.