Kuala Lampur, Jan. 23 -- When most people hear "e-commerce," they think of buying products online. But for governments, tax authorities, and regulators, e-commerce has become far more complex and crucial.

Why? How e-commerce is defined today affects how billions in tax revenue are collected, how businesses are regulated, and how consumers are protected in the digital economy.

Traditionally, e-commerce was buying and selling of goods and services over electronic networks with access to the internet.

In those days, e-commerce meant straightforward: "online retail" - a business selling goods through a website to buyers who paid electronically and received delivery by post or by downloading them from websites, for example software, online ...