This week TechCrunch reported that eBay is projecting $4 billion in Gross Sales Merchandise (GSM) for 2011 -- that is total sales volume through their marketplace, not revenue. That's 100% YoY growth in that metric.
I'd estimate that they'll do about $80 billion in total GSM this year, which means that ~5% of shopping on eBay will be done through their mobile applications. Mobile commerce is becoming real.
The article also notes that they sell 2,600 vehicles through their mobile application each week. Mind boggling.