America's ecommerce sector is primed for rapid expansion over the next five years, according to a new study by Jupiter Research.

The report believes online retail sales will jump 24% in 2004 to $65 billion (€52bn; £36bn) and then grow rapidly to reach $117bn in 2008 -- a compound annual growth rate of 17%.

Etail will remain a relatively small shopping category, accounting for just 5% of total US retail sales by 2008. However, the web will become increasingly important as a research tool, and Jupiter estimates that 30% of offline purchases will be informed by data from the internet.

The growth of ecommerce is attributed to two factors: more people buying online and a rise in average online expenditure per buyer. Jupiter forecasts that growth in the former will eventually slow, with 67% of web users making internet purchases by 2008. Average spend, however, will rise steadily over the same period to almost $780 per web shopper.

Fastest-growing ecommerce categories will include home and personal care, groceries and over-the-counter medicines, all of which will expand by over 30% a year. Established online sectors such as books and software will climb more slowly, with annual growth rates forecast at under 10%.

Data sourced from: Jupiter Research; additional content by WARC staff