It is not possible for you to know every single porn or social networking website. That's why SecureTeen makes use of categories so that you don't have to type all websites which you want to allow OR block. All websites containing similar content are placed under one group called 'Category'. For example, the 'Social Networking' category caters to facebook.com, twitter.com, orkut.com etc. If you block the 'Social Networking' category, all sites within it will be blocked. Similarly, if you allow a particular category then all sites under that category will be allowed.