A base station in a wireless communications network counts mobile stations receiving broadcast content via multi-user channel. The base station broadcasts a repeating message identifying at least one broadcast content stream and, for each stream, a REGISTER (R) or DO NOT REGISTER (DNR) indicator. Mobile stations periodically re-examine contents of this message. When the indicator is R for a broadcast content stream, mobile stations whose users have elected to receive it send the base station a registration message for that stream. When the number of registered mobile stations reaches a prescribed number, the base station changes the indicator to DNR. When the indicator is DNR for a broadcast content stream, mobile stations refrain from sending any registration message for that broadcast content stream. The base station may institute a recount by resetting the indicator to R.