These YouTube personalities have huge online fan bases. YouTube gaming channel PewDiePie, has more than 32 million subscribers, for example, according to statistical website, SocialBlade.
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The Journal says YouTube executives are especially concerned with Vessel.
The video start-up's website, which is being built now, is backed financially by Benchmark, Greylock Partners and the personal investment company of Jeff Bezos. It was co-founded by former Hulu Chief Executive Jason Kilar and that company's former chief technology officer, Richard Tom.
Vessel has raised $75 million in venture capital, according to the Re/Code and is looking to secure programming ahead of a planned launch by the end of the year.
While the start-up might pose a threat, YouTube remains fiercely popular, 100 hours of video are uploaded to the service every minute and more than 6 billion hours of video are watched each month.
Disclosure: NBC News group is a minority stakeholder in Re/code and has a content sharing partnership with it.