Revenue generated from internet advertising is set to rise by a fifth over the next four years, a new study suggests.

According to research by Piper Jaffray, global online marketing income will account for $81.1 billion (£43.1 billion) by 2011.

Senior research analyst Safa Rashtchy said: "The historically passive consumer is changing rapidly, not only becoming more informed and confident about purchase decisions, but also increasingly taking control of the consumption of information and content that used to be distributed by networks, studios, publishers and retailers."

The study also reported that as the media becomes increasingly fragmented, advertisers will have to increase their marketing spend across all platforms particularly the internet to attract consumers.

Meanwhile, social media (online videos) are claimed to be the next area of growth in the industry, as an increasing amount of money is spent on internet advertising.

A report by Thomson Intermedia claimed British firms increased their internet advertising spend by 19 per cent during 2006, investing about £235 million into the medium.