Currently in the process of happening: Patreon.

They marketed themselves as independent from political bias and as having clear-cut free speech standards. People were getting fed-up with Youtube and google picking political sides and having inconsistent and arbitrary censorship standards, as well as inconsistent application of their rules and copyright system. Even extremely mainstream people like PewDiePie having their content constantly claimed by other people for what is clearly legal fair use/parody. Basically youtubers were having inconsistent revenue and so they turned to Patreon. Especially the controversial ones such as the political commentators and edge lords. The bigger/cleaner channels tended to have less trouble with Youtube so they didn't rely as heavily on secondary revenue streams. Basically Patreon was especially useful for more niche channels or more controversial channels. And they marketed themselves that way too. They were firm that they only moderated content on Patreon itself and that they generally don't care what content you put on other platforms so long as you kept up appearances regarding the content you posted on Patreon itself and the content directly funded by Patreon. As you can see in this interview:

https://www.youtube.com/watch?v=ofpbDgCj9rw

At timestamps: 9:35 15:15 24:00

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And yet they have taken fire recently for banning Sargon of Akkad for saying the n word on somebody else's stream. Basically, they claimed to be a free-speech platform that only cared about the content on it, however they have shown themselves to care not just about the content, but about the types of people on it even if their Patreon content is clean. It's a massive deal and a mass-exodus is beginning. For example, this (very moderate, mostly centrist) youtuber losing 39% of his Patrons in the 2 weeks since: https://www.youtube.com/watch?v=Hv7hvZee-PQ;