Last Wednesday was a landmark moment for the tech industry, or at any rate for that part of it that aspires to do business in the EU. It was the day when six of the biggest companies in the world had to start complying with the EU’s Digital Markets Act (DMA) – the most sweeping law thus far aimed at regulating their activities in one of the world’s biggest marketplaces.The act – which aims to promote fair competition and limit the market power of the largest tech companies (“gatekeepers”) – has been long in gestation, and was vigorously opposed by them from the outset. So the…