The holiday season is upon us! By the end of this month, more than 65% of major online retailers will have started their holiday email marketing campaigns, and more than 20% of promotional emails will refer to Christmas. Campaign planning for the holiday season will get serious over the coming weeks. Here are some trends I foresee:

By now, the ever-earlier holiday selling season is already in full swing. According to Chad White's recently released 2012 Retail Email Guide to the Holiday Season study, last year, 60% of major retailers mentioned the holiday season at least once in their promotional emails before the end of October -- and you can assume that even more retailers are getting a head start this year.

Many email marketers love to hate the preference center. As David Baker wrote in a recent Email Insider, "The problem with the 'centers' is not that they don't work, but they work for such a small population of your customers that engage, the business value is typically negligible." I generally agree with David, but mainly because of the way so many marketers use - or underuse - their preference centers. That doesn't mean you should simply ignore your preference center or just tweak it a little. Instead, I'd suggest you reinvent and rethink the concept of a preference center.

In a recent article, my fellow MediaPost Email Insider columnist George Bilbrey took a look into the future of email marketing analytics and described three new metrics that he thinks practitioners will use in 2013. While I agree that a sea change in email measurement is coming, I believe there are far more than three new metrics that marketers will find invaluable in the months ahead. These include:

The concept of a business maturity model is helpful in a few ways. For one, it allows you to assess your present business circumstances in very particular ways, at the channel level. Second, it allows you to balance this view in a normative manner across an industry or like business circumstances in which you compete. It also allows you to expose potential gaps in what you think you are doing today, versus what you'd like to do in the future.

I recently read a statistic in the Harvard Business Review that researchers who invested in brands based on online reviews did 7.9% better than the S&P 500 index. After studying four years' worth of product reviews of 15 brands -- almost 350,000 reviews -- they found there were two major predictors of performance: one was the sheer volume of reviews and the other was negative chatter. This got me wondering: Do marketers see email performance spikes or dives based on reviews and chatter over time?

Marketers have relied on open and click-through rates as the major measures of the success of a program or campaign for the last decade plus. These metrics are good, but don't always tell the entire story. At my company we began monitoring email marketing engagement as we gathered more and more panel data (aggregated behavioral data on how actual mailbox users interact with messages) over the past year. The metrics we developed while analyzing that data provide deeper insight into program performance, even relative to other marketers' campaigns. The following are three measures we've found to be especially valuable:

With the holiday season approaching, more shoppers than usual will hit brick-and-mortar locations with shopping lists in hand -- and their inboxes in their pockets. Retail marketers have huge opportunities -- this year more than ever before -- to drive in-store purchases through emails reaching consumers as they shop. Here are some strategies for driving in-store purchases that could be implemented alongside existing holiday plans:

Two weeks ago I contributed an article here examining the pros and cons of three emerging approaches to mobile email optimization: prefab content, responsive design, and live content. But I omitted a fourth, important approach that's worthy of its own discussion: mobile-first email.Two weeks ago I contributed an article here examining the pros and cons of three emerging approaches to mobile email optimization: prefab content, responsive design, and live content. But I omitted a fourth, important approach that's worthy of its own discussion: mobile-first email.

No, this isn't another "email isn't dead" column. I'm tired of those, and you wouldn't be reading this column if you thought that email's day was done. However, as an email marketer who labors in the trenches, many of you field questions or get pressured every day to channel your energy and marketing dollars out of email and into the latest hot social network or whatever other channel is generating the most buzz and noise that day. You know email rocks, but you may have to prove it to everybody -- from clients, if you are an agency, to your …