I am truely a stupid newbie webmaster my self so please dont mind my ramblings.
I found this link to a poisson probability calculator:
http://www.anesi.com/poisson.htm
On Collins
http://buildinganempire.com
It uses an equation for determining the probability of something happening that dosent happen very often in a large amount of tries.
Like getting those signups!
Using the above tool you will see that if a site truely has a 1:1000
then its probability of getting 1 signup in 10000 is 0.00045399929762484855
so it should very rarely get 1 signup in 10000 hits.
If fact the probability of getting 22 signups in 10000 hits is just a little lower 0.00040391370432873584.
So I guess you could maybe try another 10000 hits.
But if you are looking for a 1:1000 then that 1 signup in 10000 hits should be rare.
Just some shit spewing from my finger tips :o)