I think taxes are very difficult. Personally, I think when Google or Facebook places an ad on its own (public) platform, they should have to pay a tax similar to a sales tax as they have sold themselves. Probably shouldn’t apply to the ads on google.com homepage as they don’t sell those as far as I understand.

The article mentions neutrality in taxes which is either silly or disingenuous though. Our tax code is not neutral. We openly use tax code as a way to motivate public behavior.

Ad space as inventory would be an interesting concept. It is tricky though. What is the value of something before it is sold? What is a fair tax rate? How often does this inventory adjust as you have more or fewer users? Messy.