South Korea for years has cultivated a reputation as a high-tech leader, bolstered by its big electronics companies and research universities and the government's hand in building out a broadband network.

Even so, tech companies and even government agencies aren't really sure how big an impact the Internet has on the country's economy.

On Monday, three big consultancies -- BCG, McKinsey and Deloitte – revealed the results of their attempt to measure South Korea's Internet economy by using one of the ways that governments measure gross domestic product, called expenditure approach.

They found that Korea's Internet-related companies generated 63 trillion won of spending in 2009, about 6% of total GDP. That's bigger than electrical/electronic equipment manufacturing, at 5.7%, and the automotive industry, at 4.2%.

Separately, the consulting firms estimated the economic importance of the Internet in another way –- by calculating the value that Korean consumers gain from the Internet versus what they pay for it. It estimated this "consumer surplus" to be 3.2 trillion won a year. About 40% of that, or 1.3 trillion won, is value created by time savings from Internet use.