Which numbers are most important to marketing your ROI?

"In theory," he adds, "you should start with the success metrics and ask, in essence, "What is the role of e-mail marketing in our organization, and how does it support our goals?'" When it comes to measuring engagement, Greg Cangialosi, president/CEO of e-mail services provider Blue Sky Factory, contends that clickthrough rates are key. Clickthroughs let marketers know "what in their content is driving subscriber interest," he says. "Based on the reports, they can see what really catches the eye of subscribers and what doesn't. This allows marketers to either improve or prune out content that simply doesn't ever get any clicks." Even if you track deliverability metrics on an hourly basis, bear in mind that the trends, rather than the raw numbers, are what to keep an eye on. This is especially important regarding open rates. "Some marketers could potentially pay too much attention to the open rate," Cangialosi notes. "The reason is many e-mail clients block images, so the e-mail isn't recorded as an open. This causes the open rate to be inaccurate, so it's important that marketers not rely too much on it."