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.

Contains a clear definition of virtual property that in my opinion captures the correct scope perfectly. It makes no reference to games or virtual worlds, thus recognising that virtual property may exist in all kinds of online contexts. I prefer to substitute "online resource" for the author's term "code", so that the definition is:

Virtual property is an online resource that is rivalrous, persistent and interconnected.

Rivalrous is a legal/economic term that refers to the situation where one person's use of a resource excludes all others from simultanously using it, typical of physical objects but not of digital resources.

The author goes on to argue that virtual property so defined is in need of legal protection, which I think is a more complicated proposition due to the existence of conflicting norms in real and virtual economies (see e.g. James Grimmelmann's work). For example, take is this well-known anecdote: A player buys a virtual amulet from another player on eBay. Payment is carried out and the two players meet up in the MMORPG. The seller hands the amulet to the buyer, at which point the real-world contract is completed. Immediately afterwards, the seller draws a sword, kills the buyer's avatar and steals the amulet back - all in accordance with the game's rules, which allow PvP and stealing to make the game more exciting.

The naturally layered nature of the internet leads to overlapping rights of exclusion that cause underuse of internet resources: a tragedy of the anticommons.