The United Nations Conference on Trade and Development (Unctad) predicts the number of users will reach 655 million this year, or one-tenth of the world's population, compared to 500 million in 2001.
Online growth in 2001
Asia - 44%
Africa - 43%
Latin America - 33%
Europe - 33%
N. America - 10%
The annual E-Commerce and Development Report estimates trade in goods and services over the Internet could reach $2.3bn (£1.46bn) this year, a 50% jump on last year, and could hit $3.9bn by the end of 2003.
The reported is considered a key indicator of the development of e-commerce, which is notoriously difficult to quantify.
About a third of new users were from developing countries in 2001 but the percentage of the population using the internet was still far higher in rich nations, the report said.
Global use
The US had the most users, with nearly 143 million people online, followed by China with some 56.6 million.
In Britain access rose by 33% to nearly 40% of the population.
Broken down by region, internet users in 2001 jumped 44% in Asia, 43% in Africa, 33% in Latin America, 33% in Europe and 10% in North America.
Internet use has grown rapidly in India, with 25% growth last year, to one in 147 of the population.
In North and sub-Saharan Africa, 6.7 million people were online last year, or one in every 118 people living on the continent, but excluding South Africa, Egypt, Kenya, Morocco and Tunisian, that figure fell to one in 440, UNCTAD said.
Online business
E-commerce is doing well across the globe despite the economic stagnation in the US and elsewhere, but the report said business-to-business e-commerce had not been adopted in developing countries.
The US accounts for almost 45% of e-commerce revenues, while western Europe has about 25% and Japan about 15%.
Developing countries account for just 6.7%, mainly in the Asia-Pacific region, with the rest accounting for just one percent.
In Africa business-to-business e-commerce outside South Africa is "almost negligible".
The report said that IT products now form a larger share of developing countries' exports than agricultural, textiles and clothing products combined.
This was due mainly to multi-national companies using cheap labour to produce hardware and software, the report said.