Electricity and IT are perhaps the two most important GPTs to date. We analyze how the U.S. economy reacted to them. The Electricity and IT eras are similar, but they also different in important ways. Electrification was more broadly adopted, whereas IT seems to be technologically more revolutionary. The productivity slowdown is stronger in the IT era but the ongoing spread of IT and its continuing precipitous price decline are reasons for optimism about growth in the coming decades.