Michael Rubin, who built a global business in King of Prussia by selling stuff online for big-name retailers, says he underestimated how huge Internet sales would become.

And he tips his hat to Amazon.com Inc. and its chief executive officer, Jeff Bezos, for that.

"I actually used to tell people that I didn't think e-commerce would be as big as they thought it would be," Rubin, chief executive of GSI Commerce Inc., told analysts at the UBS Global Media and Communications Conference this week in New York. "I'm now officially doing my 180."

GSI runs Web stores for clients such as Toys "R" Us Inc., GNC Corp., Dick's Sporting Goods Inc. and the National Football League. In recent years, through acquisitions, it has been branching into related online marketing businesses.

Forrester Research Inc. estimated last year that online sales, excluding travel, could go from $200 billion in 2008 to about $300 billion in 2011.

"I now think that e-commerce is going to be significantly bigger than what anyone's projecting," Rubin said.

Amazon's role? Rubin said that his outsize competitor, particularly by shipping "fast and free," is "breaking down the barriers to buying online." And that helps everyone selling online.

Amazon raked in about $20 billion in sales last year - 20 times GSI's revenue. GSI itself expects a fourth-quarter profit from holiday sales, but it has projected a net loss for the year. In the most recent quarter, it lost $9.4 million on $190 million in revenue.

Showdown delay

USA Technologies Inc., under intense fire from dissident shareholders who are promoting their own slate of director candidates, now says it has postponed the shareholder meeting - first set for Tuesday - to June 15.

The Malvern firm, whose technology is used for credit card purchases at vending machines, said Wednesday that it was reacting to "misleading, inaccurate, and selective disclosure" by the dissidents.

Mike Armstrong is away. Contact Reid Kanaley at 215-854-5114 or rkanaley@phillynews.com.