How do companies offer Ad Free websites with free video storage?

There are quite a few ad-free web services out there now such as Daily Motion, vSocial, Zippy Videos, You Tube and so on that allow you to upload videos for sharing. A few have Goggle ADs on there pages but nothing else. How is this possible in real-life?
Sorry, I'll try and clarify..... I have noticed a large percentage of these websites do not carry Advertising. There are a couple that have Google Ads implemented but quite a few of them are offering FREE video hosting and NO adverts.

what u mean by "how this is possible on real life" ?
u know they show ADS , the increase their wesite rating .
soryy if i have not understand u
please add details
thank you .

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