adult verification systems

[jmbrown1881]

OK, easy question..
I am not looking for great signups or even convertions. What I need to know is which adult verification system has the largest amount of members. Right now I am not worried about them signing up for the service, I just need to know who has the largest member base.
Thanks ahead of time..
By the way, they all claim they are the biggest and best, so if I could get honest answers, that would be great

[Mogul]

You will not get true replies because no one knows.

Adult Check and Cyberage are very big and have been around for awhile.

Sex Key is a free pass service. While newer than previous two, it is used widely and no doubt has a big user base.

Free Net Pass is coming along and is a free pass service as well.

Mogul