comScore has recently published the most recent report in their popular series U.S. Digital Year in Review. The review examines the key digital marketing trends in 2011 and talks about what they mean for the coming year. There are no great surprises, although, the degree to which online purchasing appears to be growing may surprise some.

E-commerce had a particularly good end to 2011. The advance of mobile, video and social networking are all discussed but in this post you can hear what Gian Fulgoni, comScore chairman and founder, has to say about "The future of e-commerce" followed by highlights of the most significant ideas and statistics.

• Growth in e-commerce driven by convenience and lower prices
• 2011 e-commerce sales up 13% on 2010
• End of year holiday shopping season 15% growth on 2010 compared with instore growth of 4%
• Free shipping has become the norm. 50% of consumers who were asked said they would leave and go to other sites if they are not offered free shipping.
• Avg. Non-Free shipping purchases $100
• Avg. Free shipping purchases $118
• 56% of e-commerce sites offer free-shipping, up from 50% in 2010

You can download the full report here