There is abundant proof that email, after over a decade of successful use, is not only the connective tissue of all data-driven marketing but also the revenue-producing heart of digital efforts.

Yet, despite claiming the highest ROI of all direct marketing channels at $28.50 in sales generated for every $1 of spending (DMA 2012 Response Rate Report), the highest driver of online conversions, and the number two spot (behind only search) in new customer acquisition, email marketing is still too often swept out of sight, called upon only when we need miracles worked.

In over a decade of experience with the channel, I am too frequently surprised and dismayed that email is not receiving nearly the attention and investment it deserves.

Like Cinderella in the classic fairy tale, email dutifully goes about its business, quietly completing a wide variety of marketing tasks without complaint—from prospect qualification to lead nurturing to direct sales.

It also does plenty of less-attractive, more menial labor in the transactional messaging realm, such as conveying confirmations, notifications, reminders, and alerts; and, just like Cinderella, it is frequently under-resourced and kept out of sight until needed.

But when it's needed... you'd better batten down the hatches, for email will be heavily (if not impossibly) leaned upon to achieve quarterly or annual revenue goals, save jobs, and launch new products.

Also like Cinderella, email marketing professionals will be expected to work nearly 24 hours a day with barely enough energy to stumble into bed long after midnight only to wake before sunrise to do it all over again.

I recently led a training workshop for midsize businesses on integrating inbound marketing channels, a lynchpin of which was email. When showing the many campaign examples in my teaching materials, I was surprised at the reaction from some of my audience members. "But so-and-so is a well-known company/brand with an army of marketing staff," said one. "They're a big retailer with far more people to do email than we," moaned another.