Left Y axis is page views (gray), right Y axis is unique visitors (blue). A page view is just what it say, a visitor looking at a page. A unique visitor is identified by IP. Thus it is a unique IP visiting your site. They are summarized over a day in the graph. Thus every value is per day.

The total you see below is the sum of all page views over the last seven days.

@Tanner yup, just slightly more work as you'd have to wire up the save/load calls when the homepage is loaded.

You could get away with doing the save only, if there were a hook for home page retrieval, but to my knowledge, we don't have one... (yet?)