Major online retailers began sending holiday emails on October 28th last year, 58 days before Christmas, according to a new report, "The Retail Email Guide to the Holiday Season" from the Email Experience Council, the email marketing arm of the Direct Marketing Association.

The web merchants increased their email volume by 45 percent, compared to the period before the holiday season. Two out of three sent out at least one email on the day after Thanksgiving, often called Cyber Monday.

"As marketers, it is important that we learn from past behavior," said Kara Trivunovic, director of strategic services at Premiere Global Services, Inc., which sponsored the guide. "Looking at your successes and failures over the course of previous holiday seasons will help you to avoid the pitfalls and repeat the windfalls," she advised.

"Be sure to review all aspects of the campaign, including: day and time of send, subject line, offer, audience, length of offer and conversion rates. Analyzing these facets of your campaigns should help you in building the right direction for this holiday season," she added.

There are 16 phases of Christmas when it comes to email marketing, starting with gently introducing holiday items at the bottom of emails in August, and concluding with the promotion of post Christmas sales, according to the report's author, Chad White, director of retail insights at the Email Experience Council.

Once the holiday marketing season gets under way in earnest in late October, retailers rapidly increase their email campaigns, sending 2.8 emails per week compared to 1.9 during the pre holiday period, said White. He monitors the email marketing campaigns of more than 100 of the largest online retailers. Overall, 88 percent of those top web retailers increased their email frequency during the 2007 holiday season.

That means cluttered inboxes for consumers, noted Trivunovic. "Your messaging needs to be relevant to your recipient and include content and offers that are specific to them," she said.

"Over saturation of your audience could result in list attrition and negative impacts on your brand," she warns. "If you see a steep decline in open and click through rates, an increase in unsubscribes or spam complaints, then pull back to minimize the effects of over mailing."

Other suggestions in the report include:

• Target high volume shopping days. The most popular day for sending email was the Monday after Thanksgiving, when 68 percent of retailers emailed their customers. The next most popular day was December 10, two Mondays later, followed by the day after Christmas.
• Craft subject lines carefully. Review the most commonly searched terms on your website, and the subject lines of competitors, to find the terms that most resonate with consumers. Tout free shipping.
• Use animation. Nineteen percent of the major retailers incorporated animation into their emails last year.
• Promote electronic gift cards to last minute shoppers. Thirty two percent of top online retailers promoted electronic gift cards at least once during the five days before Christmas last year.
• Consider sending a holiday greeting. Fewer than 10 percent of major retailers sent a holiday email greeting on Christmas Day last year. Among those that did were the Lands' End unit of Sears Holding Corp., and Harry and David Holdings Inc.

"Email is a relationship channel and your recipients need to recognize that every time you send a communication you aren't asking them to buy something," Trivunovic concluded.