Planet-scale applications are driving the exponential growth of the cloud, and datacenter specialization is the key enabler of this trend, providing order of magnitudes improvements in cost-effectiveness and energy-efficiency. While exascale computing remains a goal for supercomputing, specialized datacenters have emerged and have demonstrated beyond-exascale performance and efficiency in specific domains. This paper generalizes the applications, design methodology, and deployment challenges of the most extreme form of specialized datacenter: ASIC Clouds. It analyzes two game-changing, real-world ASIC Clouds-Bitcoin Cryptocurrency Clouds and Tensor Processing Clouds-discuss their incentives, the empowering technologies and how they benefit from the specialized ASICs. Their business models, architectures and deployment methods are useful for envisioning future potential ASIC Clouds and forecasting how they will transform computing, the economy and society.