All modern marketing is defined by numbers, with none more quantitatively organized than email. It is only fitting then to take a look back at some of the most remarkable numbers generated by and associated with email marketing over the past year. The data points below shed a bright light on the effectiveness of the email channel in 2012, as well as the challenges we email marketers face in 2013.

Here are email’s most staggering statistics of 2012:

1. 70% of messages marked as SPAM are legitimate marketing emails.
Consumers do not differentiate between “I never asked for this” and “This bores me – make it go away,” and are using the spam button interchangeably with the unsubscribe button. You can’t blame them really. Inbox overload is reaching a fever pitch and marketers are making the unsubscribe process more challenging, either by camouflaging the link in the footer or entreating subscribers to stick around on the unsubscribe page. For marketers, this means that the legal definition of spam is largely irrelevant and has been displaced by a consumer call for (much) greater relevancy.

2. There are more opens on mobile devices than either web-based or desktop clients.
Mobile email reached an inflection point this year, with more opens occurring on mobile devices (37%) than either  desktop clients like MS Outlook (33%) or web-based email like Gmail or Yahoo (30%). In fact, more emails are opened on the iPhone than in any other client. Mobile should not just be an afterthought in your email program; we’re at the point where we need to lead with mobile. Design, copy length, even calls-to-action should all be organized around a highly mobile audience.

3. Most of the $690 million raised by the Obama campaign was generated by email.
The Obama campaign’s use of email in its fundraising and mobilization initiatives was groundbreaking. Unprecedented big data integration and marketing automation were supplemented by good old-fashioned email best practices, taken to a new order. Instead of A/B testing a couple of subject lines, the campaign would routinely test 12, 15 or 18 subject lines, an exercise which lifted results by over a million dollars per message. Campaign directors revealed that most of the $690 million raised was directly attributable to email. Obama may have been named the victor, but it’s clear that email won the presidency.

4. Email generates $39.40 in sales for every $1 spent.
The Direct Marketing Association tracks ROI across channels annually, and calculated that in 2012 email earns brands almost $40 for every dollar spent. That is down a few dollars from last year, but is still steps above other channels: search came in at $22.38, online ads at $19.70 and social media had about 1/3 the ROI of email at $12.90 for every dollar spent. In 2011, brands worked hard to find ways for their email program to support their social channels. In 2013, I think we’ll see the opposite trend, with marketers trying to lure as many people as possible into email with its higher ROI.

5. 60% of holiday shoppers visited a physical store because of email.
We all knew about email’s superb online ROI even before reading stat #4 above. What is less frequently quantified however, is the impact that email has on offline purchases. A study that came out during the holiday season found that 60% of holiday shoppers went into a brick-and-mortar store as a result of an email they received. Social media drove people to stores only 1/3 as often, comparable to the ROI ratio above in #4 as well. What this means is that the call-to-action in an email can be more expansive than “click here, buy now!” Emails can create a brand impression that lasts longer than an online session and can drive action days in advance.

6. 1 in 5 messages never make it to the inbox.
When we look at deliverability, we might see a 98% delivery rate and assume that all but 2% of our messages reached the inbox. Actually, what that number means is that all but 2% were accepted by the email administrator or ISP and passed along to the subscriber. But as we all know from seeing messages pile up in our own junk mail folders or being filtered off to some other email purgatory, getting the nod from the ISP and landing in the actual inbox are not the same thing. Actual Inbox Placement Rates declined this year, from 85% to  82% according to Return Path. That means that almost a fifth of the people you think of as your audience never even see your emails. There are a couple of key takeaways from this statistic: 1) Keep growing your list, because the size of your effective audience is shrinking every year; 2) lift relevancy, anticipation and engagement so your messages are less likely to be filtered off on their way to the inbox.

7. 91% check email daily.
Email remains the essential digital communications channel for most people, with 91% of us checking our inboxes every day. However the role that email plays in personal communications is evolving. A 21% drop in personal emails is attributable largely to mobile and social. I don’t think this makes email any more relevant to marketers, however. Even if people switch ALL their personal communication to other channels and reserve email just for commercial messages and business, that just means that we as marketers are only competing with other marketers for attention, not with spouses and book club members and poker night buddies. Less clutter and personal distraction could actually boost the effectiveness of marketing emails.

8. Several gazillions of dollars invested in email company venture capital and acquisitions.
That may not be the exact figure, but the M&A and VC activity in the email sector was somewhere between healthy and remarkable. Email companies acquired social dashboards to evolve into digital messaging firms; technology companies bought email platforms to more deeply integrate data and communications; new email companies emerged with sizable VC backing; and existing companies involved in email began taking steps towards the public markets. There is more optimism about the future of email as a marketing channel today than I have ever seen.

So that is the email year that was. Happy New Year to you. May you keep your subscribers engaged in 2013.