The Spanish regulations apply to any e-Commerce operation involving buyers in Spain. These regulations apply to online sales, advertising, standard terms of contracts, electronic signatures, data protection, and intellectual and industrial property. e-Commerce tax issues are complex: since the vendor/provider is often located outside of Spain, sales can't be regulated from a unilateral Spanish perspective. Perhaps for that reason, the Spanish tax authorities have not adopted unilateral measures, preferring to wait until a consensus is reached on the measures to be adopted regionally and even worldwide.
FAQs:
I plan to sell online in Spain. Do I charge Spanish VAT tax?
Why is Spain a good choice for e-commerce companies?
Links:
Sample contracts
OECD report on e-commerce Discusses e-commerce direct tax and establishment issues, such as the legal status of income coming from e-commerce, the transfer pricing problem between companies that belong to the same group, and the application of the "place-of-effective-management" rule.
For further information in English, go to the Agencia Tributaria, click on "No residents", then "Vat on e-Services".
Note that privacy-of-data laws vary widely between Spain and countries such as the USA or UK.