Its relatively easy. All the big tech crops are paying effectively below 1% of their profits in Europe and are moving almost all of their profits to tax havens. As these companies are very creative when measuring their localized profits, its easier and more fair to impose a tax at the revenue level.

I don't understand all the negative comments here. Look at the big profit margins of all big tech companies (maybe with the exception of Amazon retail) and ask yourself whether a moderate, unavoidable tax is really unjustified or will have negative effects on anyone (except maybe the shareholders). I don't think so and in my opinion tech workers should be a bit more mindful when thinking about these taxation topics. I prefer paying high taxes strongly to further social segregation, which will lead to the development of civil unrest and lower quality of life for everyone sooner or later...