plugsdrugs-ish analysis of why rep boosting can be very dangerous indeed, but is not a cause for alarm
the rep of a user doesn't actually change as they start posting more. The modern definition of rep is lorentz-invariant, so it doesn't change with posting frequency. to define rep so that it is not lorentz-invariant (such as relativistic rep) doesn't really make sense. so the rep remains constant in all forums from the points of view of all users, but you can boost into a forum where the user population is arbitrarily small due to shit posting. still, though it's not possible to form a black hole of garbage posts even in one forum, so it's not a black hole of shit from the point of view of other users in the same or other forums. i hope this clears up an often misunderstood property of rep boosting and why, for all intents and purposes, rep can be disregarded.