This article explores three new concepts in property law. First, the article defines an emerging property form - virtual property - which is not intellectual property, but that more efficiently governs rivalrous, persistent, and interconnected online resources. Second, the article demonstrates that the threat to high-value uses of internet resources is not the traditional tragedy of the commons that results in overuse. Rather, the naturally layered nature of the internet leads to overlapping rights of exclusion that cause underuse of internet resources: a tragedy of the anticommons. And finally, the article shows that the common law of property can act to limit the costs of this internet anticommons.