Youtubers make money off inserted adds based off of the number of views. First you need over 10,000 views to unlock monetization of your videos. From there YouTube places adds in the videos and advertisers will pay roughly $0.18 per thousand views. Out of the total number of views, YouTube says only about 15% of the viewers watch the adds. At least 30 seconds must be watched. Some of the children channels make the most money because small children don't read, or skip adds.
How can you help your favorite youtubers?
Either pause your Adblock while on YouTube/certain channels, or you may white list your favorite channels. Allowing the adds enables the channel to earn off the advertisements. The down side to this is YouTube takes 56% of the ad revenue. Some channels add to this by inserting paid adds, reviews, etc. into the video itself but to do this they must have a large enough audience for the advertisers to sponsor them.
As an example, Pewdiepie who has over 57 million subscribers made approx 4 million last year before taxes and the YouTube cut. A childrens channel with somewhere around 1 million subscribers made 4.5 million. This is due the the lack of adblocking and skipping adds in this age/category range.
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