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Thats where the browser extention with the personalized usernames comes in... May never be truly adapted by platforms like youtube as an easy "buton" donation but the browser extention will allow a user to send a donation to any given username with ease. So say Johnny Youtuber posts a video telling his subscribers where and how they can donate with the extention... They do so and spread the word.. No integration needed.

If it's not integrated or pushed by the platform than not many people will use it. We are still very few who actually know about this. Might take of though... who knows.

Thats the beauty of a big time youtuber such as Philip Defranko or Fusey Tube finding it and making it go viral!

Philip might! But Fousey... I mean... does he even lift? ;)

Valid question