Can a regular person (or an expert) tell that you see an ad? Usually yes, as it's banner or some visually distinct piece of a web or real estate.
Can one tell that a text is produced by SEO? Usually no (especially, when it's good quality).
Now, the difference is:
- In ads case, a government comes and asks for a tax. Because there is a clear case for a transaction in an economy sense (ad for money).
- In SEO case, no transaction proof is there. Can't come and ask to pay tax, or regulate anything. It could be a happy customer who wrote a piece of text. Or clever SEO author. Or both mixed. Can't tell! In this sense SEO brings less or no tax.
Can one tell that a text is produced by SEO? Usually no (especially, when it's good quality).
Now, the difference is:
- In ads case, a government comes and asks for a tax. Because there is a clear case for a transaction in an economy sense (ad for money).
- In SEO case, no transaction proof is there. Can't come and ask to pay tax, or regulate anything. It could be a happy customer who wrote a piece of text. Or clever SEO author. Or both mixed. Can't tell! In this sense SEO brings less or no tax.