According to BPIP, there are 117 530 active forum members. By active, the site is considering all accounts that have logged-in over the past 3 months, regardless of their activity (they may or not have posted).
Regarding the general stats, not all indicators are that accurate in terms of current data, since some of them seem to consider all forum history, and not just a recent period of time which, in some cases, may be more representative (i.e. average registrations per day is one of these).
Real number of active users is much smaller, probably way less than 100k. It's very difficult to tell real numbers. Big part of these counted active users are just bots who haven't made single post. There is also more or less alt accounts too.
@DdmrDdmr, maybe you have stats how many users had made at least 1 post in 3 months? It would more accurate number of active users.