IRC is easy to migrate from since there is nothing to migrate other then chat history. IRC is also missing so many features that slack provides out the box. And

IRC is easy to migrate from since there is nothing to migrate other then chat history. IRC is also missing so many features that slack provides out the box. And a law like that would not work since you would need to write complicated transformation scripts to transform between services. Also not all services are a 1-1 mapping. I like IRC but it has its limitations. That is why slack succeeded where IRC did not.