And so since last year, I’ve found myself issuing warnings instead of accolades about the latest trend in the frothy world of cryptocurrencies: ICOs, or initial coin offerings. The initial idea was a pretty good one—blockchain technology could be used to issue new cryptographically secure “tokens” or “coins” that are easy to transmit peer-to-peer. The coins could be sold to fund open-source software projects and other services that people find useful but are hard to finance with traditional structures. They could even function as shares and thus allow startups to finance themselves far more efficiently, from a broader range of people, and without the intermediaries that take fees and require a drawn-out process. Or the “coins” could represent some unit of utility, such as a gigabyte of storage or access to a network.