LAST month, somebody bought a 10-year-old animated gif of a flying cat for over half a million dollars. It isn’t some symptom of pandemic panic, nor is it a new scam. Instead, it is all thanks to a tiny piece of code called a non-fungible token , or NFT, that offers an internet solution to a very internet kind of problem.

The problem is that art gains its value from being unique, but when you can download anything online, suddenly art doesn’t seem so valuable. The solution is the NFT, a unique digital token associated with an image …