Friedman defines a "flat world" as a global, web-enabled playing field that allows for collaboration across boundaries in real time. This flattening has occurred through various technological and economic developments that have lowered barriers preventing the flow of ideas, knowledge and work across borders. However, some critics argue that globalization has increased disparities between nations rather than creating true assimilation, and that economic activity remains clustered in certain regions, making the world "spiky" rather than flat.