Following are a few highlights from the study:

1. More retailers added email to their marketing programs last year.

Ninety-six percent of the Top 500 retailers offered email as a marketing channel by the end of 2008, a slight increase from 94 percent the previous year. The remaining retailers closed the gap, rising from 83 percent in the 2008 study to 91 percent in 2009.

2. Retailers increased message frequency.

The Top 500 retailers sent out 23 percent more email in the evaluation period, while the remaining retailers sent 39 percent more compared to the previous year. The number of top retailers that sent from 11-14 emails within the 30-day period increased from 10 percent to 14 percent.

In a positive development, significantly fewer top retailers did not send a single email during the 30-day period. In the 2008 study, 35 percent did not send a single email as compared to 22 percent in the 2009 study. This means more retailers are sending at least one email in the crucial first 30 days after opt-in.

3. Fewer retailers give recipients choices to customize their subscriptions at opt-in.

Although customization increases subscriber engagement, fewer retailers provided that option in the 2009 study.

Once again, more Top 500 retailers offer subscriber choices, but that number fell by half, from 56 percent in 2008 to 28 percent in the 2009 study. Among remaining retailers, the number fell by almost the same rate, from 26 percent to 14 percent.

4. More companies offered sales and discounts in the 2009 study.

Top 500 retailers increased discount-focused emails by 10 percentage points, from 58 percent in the 2008 study to 68 percent in 2009. While 36 percent of remaining retailers in the 2008 study utilized sales and discounts, the number jumped 17 percentage points, to 53 percent, in the 2009 study.

The severe economic pressure on retailers likely drove this surge. However, relying on email solely for this kind of promotion can turn the channel from a premium revenue producer into just a discount channel.

5. Fewer than 3 in 10 retailers offer unsubscribers the option to change preferences rather than unsubscribe.

This is another missed opportunity to salvage subscriptions and build engagement. Only 28 percent of retailers gave unsubscribers other choices to stay on the list, such as changing interest preferences, message frequency or email address.

Survey Methodology

Silverpop researchers opted in to receive email from 895 online retailers. Messages received during a 30-day period in late 2008 were evaluated on seven characteristics. Findings were compared with data compiled during the same period in 2007 and reported in our 2008 study.

Download the full study at Silverpop