Turkey has enacted Law No. 7194 with the DST. This Tax aiming digital business like Alphabet, Facebook and online retailers. The Tax rate ise 7.5 over revenue. So actual rate of Tax much more higher. Because revenue basis taxes cannot deduct expenses from revenue. Is this rate too high? European Council also proposes DST (which eventually digital advertising tax) which rate %3 over revenue. Notwithstanding this rate criticised because of excess rating. So Turkey's DST also criticised much more for excess rating.
The rate is important, because it could increase tax collection, or also cause tax evasion through a mechanism that has not yet been invented. However, each country takes its protection measures for its economy and currency circulation.
E-COMMERCE had long be exempt from tax collection. However, that tax holiday in all countries should come to an end and merchants who engage in electronic commerce and derive income therefrom should be paying that fair share of tax. This loop hole should now be close in all countries. E-commerce is a legitimate source of income and, therefore, should come under the purview of income tax collection.
AT WHAT RATE ? Each jurisdiction or country determines the appropriateness of the rate according to (i) revenue need, and (ii) non-interference or disruption of business resulting from tax collection. Therefore, tax rate comparison from jurisdiction to jurisdiction is moot.
This article might be useful for you! Coria, J. (2009). Taxes, permits, and the diffusion of a new technology. Resource and Energy Economics, 31(4), 249-271.