Note: The NtK Model for Freeware contains Stages, Steps and Gates that may vary across the five sub-categories, as described in the five columns below.

Freeware Fee App Freemium/>$5 Free  DIY Fee DIY/Training
Required Required Essential to support upgrades to the premium levels of service Not needed Modified to track the user's experience/quality of the information delivered (and enabling subscriber to opt in to getting advertisements on related materials and information