This discovery comes out of the work I did on this year's newly released Retail Email Subscription Benchmark Study. While the subscription study included more than a dozen retailers that I wasn't already tracking via RetailEmail.Blogspot, it appears that only about 6% of retailers sent onboarding emails. And two-thirds of those sent only one onboarding email.

In every case, the onboarding emails were in addition to a welcome email.

The retailers in this small group had a few different strategies for their onboarding emails, ranging from making brand introductions to simply trying to spur that first order.

For example, Blue Nile, Chadwick's and Road Runner Sports all sent a single email that hammers home their brand positioning. Blue Nile's email offers subscribers advice about buying a diamond, tells them how to search Blue Nile for diamonds, mentions some awards and accolades that the company has earned, and talks about shipping and returns. Chadwick's gives readers a little history about the retailer and offers an incentive to buy. The point of Road Runner Sports' email was primarily to stress that it offers a wide variety of brands.

Like Chadwick's onboarding email, SmartBargains offered an incentive to get new subscribers shopping. But instead of a one-time incentive, the company added a banner to the top of its emails for the first few weeks offering free shipping to new customers.

Bluefly took an entirely different tact. It sent multiple onboarding emails over a few weeks. The emails were not very different from their usual emails, except for the following: (1) they all had a secondary banner that focused on a brand message or customer service offering; and (2) the cadence of the onboarding emails was slower than their core campaign.

For example, one of the secondary banners said: "If you choose Bluefly credit on your return label, you'll get FREE shipping on all returns." Another said: "Bluefly has fabulous on-trend clothing and accessories straight from the mags and runways up to 40% off retail." Each message tells the subscriber something about shopping with Bluefly that they might not have known. What Bluefly is doing with its onboarding emails reminds me a lot of the "Did You Know..." campaign that Coach ran last November emphasizing various service offerings like gift reminders and gift wrapping services.

Regarding frequency, normally Bluefly sends six or seven emails a week. However, during their onboarding campaign, they sent emails only every third day, helping ease the subscriber into the program before shifting into high gear. Retailers with high frequencies like Neiman Marcus, Spiegel, SmartBargains, FTD and Overstock.com might make use of this tactic to more gradually ramp up their email programs with new subscribers.

Based on these onboarding emails, here are some elements to consider including in your own:

1. A sentence or two about your company's history, including the year of its founding.

2. Reinforcement of brand messages from the welcome email.

3. An explanation or statement about your shipping or return policies.

4. References to awards that you've won (but don't overdo it).

5. Links to reference guides and tools. For example, Road Runner Sports has a free training log service that the company could have mentioned.

6. Links so the reader can refer a friend or send the email to a friend.

Here are a few more onboarding email tactics worth considering, which I didn't see any retailers use:

1. Only include the "add us to your address book" language in your onboarding emails and keep them out of your regular emails. Stefan Pollard over at EmailLabs has argued -- and I agree -- that this language takes up valuable real estate, and if your readers haven't complied after seeing it a few times, they probably never will. No sense wasting space on it email after email.

2. Promote your blog, forum, social network, video library, etc. For instance, Bluefly could have mentioned Flypaper, its blog. While you're welcoming consumers into your email community it's a perfect time to let them know about the other ways they can take part in your brand's community.

This commentary is insightful. I recommend it to others.