While unlikely, I personally believe that advertising revenue should be taxed at 50%. This would do a lot to align industry incentives. Advertising revenue would be looked at less as a free cash stream that can be bolted on everywhere. In this case, maybe the app could be monetized directly instead of whatever the fuck is happening now.
Revenue isn't taxed. Profit is. I suppose you could tax a proportion of your profit at a higher rate, according to the proportion of your revenue that came from advertising. But advertising isn't a "free cash stream that can be bolted on everywhere". It's part of a business model that either is sustainable or isn't. If you taxed it that much higher, a lot of businesses would simply go out of business, because people…
What about VAT ?