Valve and Github are well-known for open allocation, which is different from "flat organization". You can both, either without the other, or neither. "Flat" or

Valve and Github are well-known for open allocation, which is different from "flat organization". You can both, either without the other, or neither. "Flat" organization is unstable and therefore probably not desirable. Open allocation (people can transfer freely as they wish) is a good thing and the only way to function at high levels as a technology company.