> Good, hopefully we'll see some real innovation, with wide spread micropayments

Micropayments raise difficult tax issues, especially for small sites.

In the United States, for example, if I've counted correctly 34 states require or will require by early 2019 out of state sellers of goods or services into the state to collect, report, and remit that state's sales tax. Another 13 states could do so, but have not yet amended their laws to require it [1]. 4 have no sales tax at all. (I'm counting DC as a state here).

Whether or not a state actually can force this on a given seller depends on whether or not the seller has a "nexus" with the state. 24 states' laws say you have a nexus if you have 200 sales a year in the state or sales in a year totaling $100k.

With micropayments, a site could hit 200 sales in a state easily and have to deal with sales tax, while only earning a small amount of revenue. For example, suppose your site accepted micropayments for reading articles. Say you did $0.05 per article. If 200 people in a "200 or $100k state" bought articles, that would $10 revenue.

Congratulations...you have to collect tax on that! Worse, tax depends on exactly where the person lives in the state. You have to get their address, and lookup the tax based on that. Going just by state, or even just by zip code within the state, is not sufficient as you might collect too little [2]. You also have to file quarterly tax reports, which have a filing fee in most states, which will almost certainly swamp your $10 revenue.

There are services you can use to do this for you. 24 states have banded together and formed a Streamlines Sales Tax group (SST), letting you register and file and remit taxes for all 24 through a single entity, and they have agreed to provide tax data (rates and tax district boundaries) in a common file format. Even better, if you agree to collect tax for all 24 of those states, then the states will pay the costs of you using any of several third party tax services companies (Avalara, TaxCloud, TaxJar, and a few others), including the costs of using those company's APIs to handle all the lookups up and calculation, and the costs of preparing and filing the reports.

Unfortunately, there are some big states that are not part of SST. California, Texas, Pennsylvania, Illinois, Colorado, New York for example. CA, TX, and NY don't collect on out of state sellers (yet), but those others do.

Avalara, TaxCloud, TaxJar, etc., can handle those states for you too, but that won't be free. TaxCloud, for example, if you use their "automatic compliance" plan, which requires collecting tax in all the SST states (so that the SST states pay TaxCloud), you can add non-SST states for 0.5% (less for large volume sellers) of your revenue in each such state, and that will cover address verification, tax lookups, reports, and filing. (No affiliation with TaxCloud. I just happen to be using them for my first attempt to get our site at work to handle out of state US sales taxes--before we had just been collecting for sales in our own state and collecting VAT for EU sales. VAT is vastly simpler since it is per country, and the EU has something equivalent to the US Streamlined Sales Tax called VAT MOSS, so VAT was pretty trivial to deal with without needing an outside service).

Anyway, all of the above probably will dampen interest at a lot of sites. Especially having to collect address information to calculate the tax. That raises privacy issues that I think many will find more troubling than the current ad site privacy issues.

[1] It was only in the middle of this year that it became legal for states to require out of state sellers to collect. In 1992, the Supreme Court had ruled that it was unconstitutional for states to do so, unless Congress specifically authorized them to do so. Congress never did so. But this year, the Supreme Court revisited that issue and decided that it is OK, after all.

[2] Realistically, the state probably won't come after you for the difference or penalties, but it is a risk you need to evaluate.