About custom categories
A category is a collection of website URL addresses and domains. When you buy your Smoothwall Filter, it comes with built-in categories, Custom blocked content and Custom allowed content categories, which you can add and remove content but you can't delete these categories themselves. However, you can add your own custom categories, which you can delete.
If you are a large school or organization, you might require more than one Smoothwall Filter. This means that you might have a multitenant setup. You can create custom categories that you can use on any tenant or you can create tenant specific custom categories. This can be useful in situations, for example, you have a lower school tenant and an upper school tenant and you want the upper school to be able to access social networking sites but you don't want the lower school to have access. Or a more complex situation where both can access Facebook but only one can access Twitter. Therefore, you would have a social networking policy for both schools, but each would be setup to their own requirements.