Indeed, with the sophisticated filtering techniques available today, it’s a simple matter for repressive regimes to, say, disrupt access to opposition media at strategic moments during and after a presidential election, or knock out YouTube. “In the early days, countries used relatively crude blocking mechanisms at the national backbone level, or imposed restrictions upon ISPs that were applied in uneven ways,” Deibert told Technology Review. “Now we see first and foremost that many countries are using commercial filtering technologies, most of which are made by U.S. companies. That’s providing them with a finer-grain level of service.”