Just like many other areas whose activities have been deeply changed, or at least somewhat influenced, by the overall rise of the Internet in the last 20 or so years, Internet Commerce (aka E-Commerce) is still in its infancy as compared to the natural "physical" commerce.
Although many would argue over whether a book purchase on, say, Amazon would actually constitute E-Commerce (since the book is still a physical object which is, at some point, delivered through regular post to your door), none would say that business transactions conducted over the Internet are exactly the same thing that's been going on for years. In other words, E-Commerce just isn't "more of the same".
In this regard, many forces that today regulate the rights and duties of the two sides involved in every business transaction (consumers and companies) have to be throughly updated(or at least substantially modified) to account for the subtleties that arise in Internet trade.
By that I mean that most countries (if not all) still haven't woken up to the fact that their legal framework (which is the main force, other than market forces, that regulate trade) needs to undergo radical change to provide the same level of support they do for people and for companies who engage in online trading as they do for regular trade.
What I personally see nowadays is that E-Commerce just works (even across country borders), mainly due to market forces such as competition even though there's no basic law governing this trade. This is particularly true for commerce that happens between, say, a consumer in Brazil and an American online company. Just to understand the legal intricacies involved in this process would be a good theme for a doctoral thesis.