Currently showing as 13,492 on the page. Don't know if that's only those of us who have been able to verify their signatures though!
I pointed someone at it this afternoon and got the obvious question: if one signs it, may one's name become public at some stage? Did anyone look into this carefully enough to know? For myself I decided I'd sign anyway, but there are probably quite a lot of people who will only sign if they know that won't happen. Though of course the more signatures there are, the more safety in numbers.