Views refer to the number of requests to your site each month. These are tracked much like an analytics 'pageview' - and are incremented with each page or API request. We never disable sites for traffic spikes, so no need to worry about the front page of Reddit or HN. If you exceed your limit consistently on a 3 month rolling average, we'll just let you know that you need to upgrade.
Staff users refers to the total number of team members invited to Ghost Admin whom you collaborate with. For the purposes of billing, we only count users who have logged in at least once in the last 30 days.