• by Mark Walsh  @markfwal, June 7, 2011

In the last two years, eBay has emerged as one of the early leaders in mobile e-commerce. Apps created by the online auction giant for the iPhone, Android devices and other mobile platforms have been downloaded more than 40 million times.

While mobile is still a small part of eBay's $9 billion in annual revenue, it is rapidly growing.

Looking at gross volume sales, the total volume in dollars of transactions across eBay and related trading sites was $610 million in 2009 and just under $2 billion last year. It is expected to double again in 2011 to $4 billion, according to the company's Vice President of Mobile, Steve Yankovich.

In a conference call with equities research firm MacQuarie Research this week, he outlined some of the trends eBay is seeing in mobile. Among the findings:

*Average order values for mobile transactions are higher than on the desktop, which is the opposite of what might be expected.

*Mobile consumers are willing to purchase across a wide variety of merchandise categories. Furthermore, eBay has seen no barrier in terms of the transaction values that people are willing to spend on mobile, with 2,000 cars per week bought and sold on the company's mobile platforms globally.

*When it comes to tablets, between 20% to 30% of all iPads sold have downloaded the EBay app, with traffic highest from 5 p.m. to 11 p.m. Also, the auction format has proven more popular on mobile than the fixed-price model, which allows people to buy or sell items instantly at a set price -- while the reverse is true on the iPad.

*Globally, eBay's m-commerce business is growing faster in the U.K. and Australia is growing faster than in the U.S. Rising smartphone adoption in emerging markets also make them attractive growth opportunities for the company.

*A growing number of eBay customers are coming to its online market via mobile, which it will provide more data about in the future. To boost its local mobile efforts, eBay last month agreed to buy Where Inc.

Best known for its location-based discovery mobile apps, Where also runs a hyperlocal ad network, Where Ads, which processes some 2 billion ad impressions monthly. As part of the deal, eBay payments unit PayPal is expected to integrate its payment service into Where's mobile apps.