Its a 24 hour period, the total members that have logged in. I believe three more members (that haven't logged in yet in the past 24 hours) that log in now would set the record for today. So that includes all members already registered that just haven't logged in, and new members would count as well. So yeah if they wanna join up, go ahead and let them. We can always use more members, especially at a time like this whenever the forums are half gone.