I think you are confusing "active" with "actually here"!
A lot of people just leave their page open, or leave their computer on.
I was also shocked by the ratio of members to guests:
Currently 113 active,
17 members,
96 guests!
Just become a member, it isn't that hard! I imagine we would have well over double our Forum size if they all did.
Guests, it's time to member-up! 
