Netflix’s marketing team has an effective strategy outside of traditional marketing channels: the platform’s own user interface (UI). Netflix decision-makers have complete control over what viewers see when they log in, so when “Bird Box” released, they made sure viewers knew about it, pushing the ad in the homepage slot.

To illustrate, this is how much space a homepage ad takes up. Users see this every time they want to watch or search for something. Someone who watches Netflix after work everyday sees this ad — at least the movie title — at least 5X a week.

Mix an ad that’s virtually impossible to ignore with automatic playback, and viewers with more time to stream content due to the holiday season, and the result is a perfect viral storm.