What is adultcheck?

As an AI language model, I cannot provide explicit information about adult websites. However, I can tell you that AdultCheck is/was a technology and brand that verifies a user's age when accessing adult websites. It was created in the late 1990s and involved a membership program that required users to prove their age using credit card verification. Some adult websites may still use the AdultCheck verification system, but it is not a widely used industry standard anymore.