In August, the U.S. Treasury’s Office of Foreign Assets Control (OFAC) sanctioned the cryptocurrency platform Tornado Cash, a virtual currency “mixer” designed to make it harder to trace cryptocurrency transactions—and a worldwide favorite money-laundering platform. Americans are now forbidden from using it. According to the U.S. government, Tornado Cash was sanctioned because it allegedly laundered ...

In 2008, Paul Graham mused about the cultural differences between great US cities. Three years earlier, Graham had co-founded Y Combinator, a “startup accelerator” that would come to epitomize Silicon Valley — and would move there in 2009. But at the time Graham was based in Cambridge, Massachusetts, which, as he saw it, sent a different message ...