Ads, basically. But I doubt web makes any impact here. Let's say every web user spends 2 hours every day waiting for ads to finish loading. 2 hr x 100 watt x 36

Ads, basically. But I doubt web makes any impact here. Let's say every web user spends 2 hours every day waiting for ads to finish loading. 2 hr x 100 watt x 360 days x 5 billion users = 1 TWh. The US alone produces 4000 TWh per year.