Earlier quoted context omitted.
What if I post a Spanish story to HN (or Reddit) and use the title of the article as the submission title? Will the company hosting the site have to pay up?
NO, because neither Reddit nor HN operate in Spain, and therefore are not subject to Spannish law.
Maybe you are not aware of the new EU VAT on digital downloads, which is taxed in the country of purchase, not country of sale.
http://www.theguardian.com/small-business-network/2014/nov/2...
The way discussion on taxation is going globally I wouldn't be surprised if more legislation heads this way, or at the very least a presence test is applied to see if the company has a physical office in country.