Online retail sales during the holiday season increased by 15% in 2011 compared to 2010, according to data from Monetate.

Sales at brick-and-mortar stores increased by just 4% in the same period.

With a slew of imaginatively-titled shopping events during the Christmas period, ranging from Black Friday to Green Monday, there are now several benchmarks for retailers to compare their sales against.

For example, online sales on Black Friday, which fell on November 25 2011, increased by 26% to $816m compared to 2010.

With e-commerce proving to be such a growth industry, Econsultancy recently asked three industry experts for their reflections on 2011 and predictions for 2012.

Monetate produced the below infographic that compares the year-on-year sales for a number of annual sales events, as well as explaining their origins.