In combination with video content transmitted by a video streaming service, additional content may also be displayed to viewers. The video content may be displayed in a video player display, while the additional content may be displayed in an additional content area, such as an inline frame. In some examples, the display of the video content and the additional content may be synchronized such that portions of video content are displayed along with corresponding related portions of additional content. The additional content area may also receive user input. In some examples, the user input may be provided back to a source of the video content, such as a video game that generated the video content. In some examples, timing information may also be provided along with the user input, such as a time associated with a simultaneously displayed portion of video content.