In essence, when a cryptocurrency becomes sufficiently decentralized, as the widely popular bitcoin and ether have, the agency no longer views it as a security. In contrast, smaller initial coin offerings, or ICOs, are almost always securities in the SEC's eyes. That distinction matters, because securities are subject to the same regulations as normal stocks.
“Based on my understanding of the present state of ether, the Ethereum network, and its decentralized structure, current offers and sales of ether are not securities transactions,” Hinman