YouTube is the defacto destination for people to find and watch videos of different kinds, mostly user generated content as well as paid content. Lately, YouTube has added the ability to watch cable and broadcast tv as a premium member. The primary way YouTube makes money is through video ads and iirc users make a cut of the video ads money for their video uploads.
YouTube was intended to be the one stop shop for all kinds of video for all kinds of content for all types of people world. From that perspective, we need to see how widely is YouTube available, how the audience values YouTube and whether YouTube as a business is successful or not. Given the above, we should look at reach across the world, we should look at user engagement and finally we should look at earnings.
1. Reach - most widely used video service in the world, as measured by the number of users on the service every month, by the number of users uploading content monthly.
2. Engagement - YouTube users use YouTube for a variety of reasons mostly for entertainment and also for education. Entertainment is a daily need of human beings thus, daily usage is a valid measure of engaged users - DAU, we can also see whether YouTube has depth engagement so we only count users with more that 1 video watched or minutes of video watched. People also use YouTube for education so a daily habit is a valid metric.
3. Revenue - YouTube is costly from an operational cost perspective. Therefore, at its current state of the business, it is expected to earn enough to drive net positive contribution to google overall business. As costs are tight ly related to video being watched, revenue per hour of video streamed may be an interesting metric.
4. Brand impact - YouTube carries risk of legal and brand damage due to pirated and offensive content. Net positive contribution to Google brand needs to be measured. One way to measure brand impact would be monitor piracy takedowns per thousand videos for e g
5. Further, YouTube has impact on society in different countries in different ways with access to free lectures from the best teachers and authors. YouTube has also allows for harmful content. It would also be important to measure offensive content notifications per 1000 videos