how to analyze sales activity on free channel

We have just launched our first free channel, and would like to know what the traffic report means.

If I choose Sales Activity and check Show 0.00 items" then I see a lovely table with a date and a number next to it.

What does this represent?
Viewers adding the channel?
Individual viewings of an episode?

If it is the latter, how do I know which episodes are being viewed?

Thanks in advance