Hi there,
I think there are a lot of people who aren't ready for the whitelist approach because they use many informational sites that netfree doesn't know about, but want to protect themselves from images by using Netfree's human filtering.
Such a person might want a blacklist of sites you know are bad, but would want to use sites you don't know about, making it a blacklist instead of a whitelist.
Have you considered making a lower tier available where a user can pay for the image filtering functionality without the whitelist?
Thanks