eBay said Wednesday that the value of goods sold in the U.S. through its mobile applications surged 133% to $100 million during the month before Christmas. Globally, the growth was even stronger: Up 166% to $230 million worth of goods. That is good news from one angle. eBay is having success using mobile devices to sell goods during the busiest retailing period of the year. But it obscures another fact: Mobile sales may be a growing market, but it’s a tiny portion of eBay’s overall sales. And overall sales don’t appear to be growing nearly as fast. eBay’s Gross Merchandise Volume (the total value of all goods sold through eBay) was $48.3 billion in 2009, excluding car sales, and that figure is likely to top $50 billion in 2010. The $230 million GMV of mobile sales is equal to only 0.5% of eBay’s total GMV last year. Put another way, the volume of goods sold through mobile devices during the holiday season is about 6 percent of the average volume of goods sold each month on eBay. Overall, eBay’s holiday business grew but not as fast as other online retailers. According to ChannelAdvisor, a software company working with online retailers, eBay’s holiday business increased 11% during the busy Thanksgiving weekend, lagging the 68% growth rate for Amazon and the overall e-commerce growth rate of 27%. eBay has a chance to use the growing popularity of its mobile apps to boost that growth rate in coming years. But if it wants to grow as fast as the rest of the e-commerce industry does during the Christmas season, it needs to find some additional incentives.