When I think of the context of a story, two different things come to my mind. The context that I am in physically and the context in which the story is presented, no matter the platform. Both contexts affect my engagement.
The environment, or context, in which I am reading a story (or listening or watching) can either distract or help to engage me. For example, a darkened theater keeps me focused on what is happening on screen, while at home on the couch, I am often using my computer while watching TV, making it so I am not completely focused on any one thing. A noisy background, conversation, loud noises, can all take away from my engagement with a story, while a quiet atmosphere helps me to focus.
The context of the story or writing is also very important. Online, for example, the website on which a story is found changes my expectations of it. I expect ESPN to have sports stories and I probably wouldn’t engage with a story that didn’t fit in that category. Additionally, if the space a story is presented is too busy, perhaps filled with advertisements, I am less likely to focus or even stay on the page.
To reach an audience most effectively, you need to take these factors into account. For example, if you know most readers/viewers might be in a distracting environment, keep the story short and easy to follow. And as you plan your story, think about the context it will be presented it. The two should relate and work together.