The worldwide business-to-business Internet commerce market will boom to $8.5 trillion in 2005 despite economic slowdowns, according to a Gartner report. According to the report, B-to-B Internet commerce sales totaled more than $433 billion in 2000, up 189% from 1999, and are expected to more than double to $919 billion in 2001.

"Our forecast is based on the value of B-to-B goods and services sold, resold, and brokered over the Internet through establishments every time they're turned over," Lauren Shu, research director for Gartner's e-Business group, said in a conference call. Gartner based the forecast on a model of B-to-B sales transactions completed during the last five months in 22 vertical industries across five geographical regions.

Shu says the numbers are revised downward from a similar study last year because of economic slowdowns, particularly in the United States, that will slow growth of Internet commerce. Nonetheless, she said, downturns will to some extent encourage E-commerce as companies turn to it as a cost-saving measure.

Additionally, Shu says the slowdown can be viewed as a reprieve for those companies that haven't kept up with E-business, providing an opportunity to catch up. "This is not a time to retrench," she said. "The slowdown can afford them an opportunity to get their house in order."