From the article, better contextual targeting appears to be the goal of WaPo's project:
> The Zeus platform monitors contextual data such as what article a person is reading or watching, what position they have scrolled to on a page, what URL they have used to arrive there and what they’re clicking on. The publisher will then match that data to its existing audience data pools, which it has accumulated over the last four years, to create assumptions on what that news user’s consumption intent will be. The technology uses machine learning to decipher the patterns.
> The Zeus platform monitors contextual data such as what article a person is reading or watching, what position they have scrolled to on a page, what URL they have used to arrive there and what they’re clicking on. The publisher will then match that data to its existing audience data pools, which it has accumulated over the last four years, to create assumptions on what that news user’s consumption intent will be. The technology uses machine learning to decipher the patterns.