With ScreenSteps, you get unlimited viewers, unlimited content, and unlimited storage.
You are charged for the number of active authors and the number of knowledge bases (i.e. sites).
For example, you could have a knowledge base for Administrators, and a separate knowledge base for the Sales team, and a separate knowledge base for the Financial department.
You can have as many authors on your account as you want. Depending on your plan, you are limited to how many of those authors are active at one time.