YouTube video quotas are limits set on the number of views of a video or the number of calls to a playlist on a specific website or domain. These limits are established by YouTube to regulate and monitor the use of video and playlist content. Quotas can be used in various ways, such as limiting the use of content for commercial purposes or ensuring that a video is only used on specific websites. When a quota is reached, the video or playlist may no longer be displayed on the affected website.