Mobile commerce has been a big headliner this holiday season. Home goods retailer Wayfair.com, for example, reported revenue from mobile growing 75% on Cyber Monday, the Monday after Thanksgiving, compared to a year earlier. And IBM Corp. says that more than 18% of traffic to its retailer clients’ web sites came from smartphones and tablets on Cyber Monday, a 70% increase over Cyber Monday 2011, and mobile devices accounted for nearly 13% of online sales that day.

Now online marketplace eBay says last Sunday, Dec. 9, was its biggest mobile shopping day ever. EBay’s mobile payment volume, that is the dollar value of items purchased on eBay via mobile phones and tablets, grew 133% on that day compared to the largest day in 2011, which was Dec. 4.

Meanwhile PayPal Mobile, the mobile version of eBay’s online payment arm PayPal, posted 221% year-over-year growth in global mobile payment volume on Dec. 9 compared to the second Sunday in December 2011—reflecting a 204% increase in the number of people using PayPal Mobile compared to the same day last year. The company now predicts it will reach $10 billion in mobile transaction volume on eBay and $10 billion in mobile payment volume on PayPal by the end of the year.

“Just four years ago mobile commerce barely existed,” says Steve Yankovich, vice president of mobile at eBay. “Today, mobile touches nearly one in every three purchases on eBay.” That means at some point the customer used a mobile device while interacting with eBay.  For example a consumer might use a smartphone to place a bid, or to make a purchase. Often consumers go from mobile to desktop and back again, an eBay spokeswoman says.

 In an effort to help drive more mobile transactions, eBay launched a mobile shopping app in August called eBay Now that lets consumers in San Francisco and New York order online from retailers including Macy’s Inc., Target Corp., and Toys ‘R’ Us  and have their purchases delivered the same day, oftentimes, eBay says, in less than one hour.

Macy’s is No. 21 in the Internet Retailer Mobile 400, Target is No. 34 and Toys ‘R’ Us   is No. 50.