If this leads to a mass exodus from Freenode, it'll probably significantly reduce overall IRC usage.
Communities will fracture, people will set up random splinter networks that will die off in a few months, and lots of open-source projects that already want to be using something Javascripty like Slack or Discord are going to use this as the motivating thing to make the switch.
Personally I'm staying put on Freenode because I don't see a lot of user-facing impact potential here, and IRC was already essentially untrusted/public (yes, even your private messages - you don't really know who is relaying them and how trustworthy they are).
Communities will fracture, people will set up random splinter networks that will die off in a few months, and lots of open-source projects that already want to be using something Javascripty like Slack or Discord are going to use this as the motivating thing to make the switch.
Personally I'm staying put on Freenode because I don't see a lot of user-facing impact potential here, and IRC was already essentially untrusted/public (yes, even your private messages - you don't really know who is relaying them and how trustworthy they are).