The top online retailers sent each of their subscribers 3.2 promotional emails on average during the week ending Apr. 1, 2011, according to Chad White, research director at Responsys and author of the Retail Email Blog. That’s flat week-over-week, up 12% from where it was four weeks ago, and up 18% year-over-year.

However, during February and March 2011, average retail email volume has been up substantially from where it was a year earlier. The highest average number of emails top online retailers sent their subscribers in any given week during the equivalent period in 2010 was 2.8 (week ending March 19, 2010), while this year it was closer to 2.9 (week ending March 4). It is also worth noting that Easter arrived on April 4, 2010, as opposed to April 24 this year. Yet even accounting for the normal bump in retail email volume in the two to three weeks before Easter, March 2011 still outperformed March 2010 by a healthy margin.