For an online retailer, going global isn't easy. That's because retailers have to figure out how to deliver products to consumers around the world cost effectively and how to process payments online while minimizing risk. Now this sounds simple enough -- just take credit cards and use FedEx -- except that international shipping isn't exactly cheap and not all customers around the world are comfortable using credit cards.

But these two barriers appear to be falling, as shippers get more affordable and the world increasingly adopts credit cards. According to Internet Retailer, ecommerce spending on Visa cards increased a whopping 44% last year, up more than $20 billion.

And Batteries.com worked with DHL to lower intl. shipping costs by more than half. This is allowing the company the go after those 11 foreign markets that it departed from just last fall.

As the many global barriers to success -- payment processing, delivery, customer support, returns management -- continue to fall, the pressure on retailers to look beyond borders will increase. That's not to say going global is going to be easy, but it will at least be doable.