Global internet users will total more than two billion by the end of 2010, according to a report from the UN, which also said user numbers had doubled between 2005 and 2010.
But while 71% of populations in developed countries are online, only 21% have connections in developing countries, according to UN agency the International Telecommunications Union (ITU).
Africa was found to be lagging the most, with user penetration estimated to reach 9.6% by the end of the year.
According to the report China is now the largest internet market in the world, with more than 420 million users.
By the end of 2010 there will be an estimated 5.3 billion mobile phone subscriptions worldwide, including 940 million subscriptions to 3G services, said the ITU.