The metric represents the estimated number of distinct viewers who watched a video within a specific time period. If one individual watches a video multiple times, that only counts as one. For instance, if three people each watch a video twice, the view count might be six, but the unique viewer count would be three.
Understanding this metric offers a more accurate picture of a video’s reach than the overall view count alone. It helps creators gauge the actual size of their audience and assess the effectiveness of their content in attracting new viewers. Historically, YouTube’s algorithms have evolved to place greater emphasis on audience engagement, making this a key indicator of a video’s performance and potential for promotion.