What does the Quantcast ‘People’ number in publisher profiles mean?

The People number aims to describe the actual number of human beings viewing a web property: One of the several issues with using the pure ‘cookie-counting’ methodology is that it does not account for the same person visiting the same site from multiple computers. The same person is visiting the site, but they are being counted as if they were two. You can read more on Quantcast’s methodology here.