Worldwide Ecommerce From One Location: What requirements are there from other states and countries?

Details: I plan to sell downloadable information through passive search-engine ads, which could end up anywhere. I am hoping that US copyrights will be sufficient (can I do better?).

My unbacked assumptions include:

• Exemption from needing to collect taxes from buyers outside my state (e.g., sales tax nexus, state income tax returns, etc.).
• Exemption from needing permission from other states and countries (e.g., foreign LLC registrations, fees, etc.).
• Exemption from needing to add locale-specific things to the terms of agreement, or to the transaction (e.g., translations, specific clauses, currency options, etc.).

If possible, provide sources. I have not seen anything official. “No news” is not always “good news” because simplicity and ignorance do not always prevent punishment.

Is ecommerce essentially as easy as just getting a city business license, home-state filings, and a federal EIN —- regardless of what customs & laws other states and countries have?

some basic questions

1. are you the copyright owner or do you have permission to on-sell the digital downloads in question. The penalties for commercial infringement can be criminal under some jurisdictions
2. copyright is international and defaults at point of creation but it helps to register it in some countries eg China where it is a prerequisite for collecting damages from others who attempt to infringe. Who are you attempting to protect your copyright against and what effort-reward is justified?
3. eCommerce is governed by Vienna Sales of Goods but you may be caught by various Fair Trading acts (fit for purposes or false advertising) in the purchaser's jurisdiction. So have you thought about a refund policy or credit card reversal?

International taxes/duties are a royal pain. Technically the importer/purchaser is responsible for paying any additional taxes but practically it is near impossible to enforce. Basically a sale is a contract so you need to make sure that the obligations are clearly spelled out including definition of what you are selling (technically a grant of license to copyrighted material).