Methods for serving interactive content to a user

A method comprising, during a first time period:

• accessing a first digital ad comprising a first sequence of frames;
• compiling a first subset of frames, in the first sequence of frames, into a first image file;
• compiling a second subset of frames, in the first sequence of frames, into a second image file;
• and
• at an electronic document rendered by a computing device accessed by a user:
• in response to a first scroll event locating a first media player at a first vertical position within a viewing window of the computing device, rendering a first frame of the first image file within the first media player;
• in response to a second scroll event moving the first media player over a first sequence of vertical positions above the first vertical position within the viewing window, rendering the first sequence of frames of the first image file within the first media player, the first sequence of frames corresponding to the first sequence of vertical positions of the first media player within the viewing window;
• in response to a third scroll event moving the first media player to a second vertical position above the first sequence of vertical positions and moving a second media player into a third vertical position, below the second vertical position, within the viewing window, the second media player located below the first media player within the electronic document:
• rendering a final frame, in the first subset of frames, within the first media player;
• and
• rendering an initial frame in the second subset of frames, within the second media player, the initial frame in the second subset of frames succeeding the final frame in the first subset of frames within the first sequence of frames of the first digital ad;
• and
• in response to a fourth scroll event moving the second media player over a second sequence of vertical positions above the third vertical position within the viewing window, rendering the second sequence of frames of the second image file within the second media player, the second sequence of frames corresponding to the second sequence of vertical positions of the second media player within the viewing window.