Currently: With 150,399 members, I estimate that 47,903 accounts have been used by humans and 10,622 accounts are active. "Used by humans" = (received a PM and sent a PM) or at least 2 posts. "Active" = activity > 14 and logged in within the last month.
What's the period of time for the "most online" measurement, is it 24 hours? Seems kind of slim!
That's not being tracked anymore, so that statistic may be wrong.