The Boston Consulting Group (BCG) projects that the Internet economy of the G-20 will reach $4.2 trillion in 2016 - almost double  the size it was in 2010.

Not surprisingly, the biggest driver is the spike in Internet users worldwide, from 1.9 billion in 2010 to 3 billion in 2016. Increased use of mobile devices, notably smartphones, and the growth of social media are compounding factors, notes BCG.

Interestingly, BCG predicts that the falling costs of smartphones will result in about 80 percent of all Internet users accessing the web by mobile phone in 2016.

Many consumers, as we know, research products online before they purchase them offline. BCG reports this is worth $1.3 trillion of goods or 2.7 percent of GDP in G-20 countries, representing at least $3,000 per connected household.

Businesses that realize the potential and make extensive use of the Internet and social media to sell, market and interact with their customers will perform better, understandably, than those who don't.

Paul Zwillenberg, coauthor of The Digital Manifesto: How Companies and Countries Can Win in the Digital Economy says: "We are still only at the beginning of realizing the potential of the Internet. To compete, companies need to strengthen what we call their digital balance sheets by building their digital assets and reining in their digital liabilities to create digital advantage."