I’ve long been a proponent of what I call Email in the Marketing Mix (in this blog from 2009 I admit to being obsessed by the concept). Email is an extremely powerful channel, but is impact is amplified when it is integrated with other channels. This integration can take a number of different shapes, such as spreading email content over social channels, incorporating social content into newsletters, or previewing one channel’s content in another in order to build anticipation. But the premise for all of these tactics is the same: your audience lives in multiple channels, and the best way to keep them engaged is through content as tailored to the channel as it is targeted at the audience.

As your brand expands into multiple channels, then, there is a double opportunity available. First, you can engage the audience within that channel, with content and promotions designed expressly around Facebook, Twitter, LinkedIn or mobile. So make sure you do that, in order to cement your audience’s attention and ensure that the channel they’ve chosen is valuable to them. Second, you also have the opportunity to bring these audiences into your email program, which already has demonstrated ROI and dedicated resources. If you are sending an email to 25,000 people now, it is no more work (and very little incremental expense) to send it to 30,000. And if you choose which 5,000 people to add to your list, wouldn’t you select the people who are already aware of and engaged with your brand somewhere else? Not only are they more likely to respond to your email (boosting engagement metrics and deliverability), but they are also more likely to help spread your content through the other channels.

Here are 5 ways to bring social and mobile audiences into your email program, to boost the reach and impact of your communications across all channels:

Social:

1. Dedicate A Facebook Timeline App: The Facebook Timeline layout for pages that launched earlier this year presents an enormous boon to email marketers. The new layout incorporates icons for four Apps merchandised right on the cover photo (and more apps that open up from there). Devote one of these to subscribing to your email list to bring your fans into your house list. Many apps are available to facilitate this process, allowing you to simply import your existing subscription page URL or set up a custom subscription page using plain old HTML. (We like Woobox but there are many others.)

2. Proof of Concept: Why simply mention your newsletter when you can actually show it? Post web versions of your newsletters in all of your social channels so that your audiences there can experience them first hand and decide if they would like them in the inbox as well.

3. Use List-Building Promotions Socially: “Enter to Win” sweepstakes are not particularly cutting edge, but they work. And when they work in social channels, not only do they bring your social audience into your email program; they also help reach a larger social audience through the content sharing features integrated into social media. Just be sure to organize your promotion so that it is relevant to your brand and will attract people interested in you, not just interested in the prize. For example, if you are a hotel, give away a 3-day weekend at your property, not an iPad.

Mobile:

4. Turn Analog Points of Contact into Subscription Engines with QR Codes: Nowadays, most people are “mobile” all the time, every day. So the opportunity to reach them with some sort of mobile initiative happens with every point of contact. Make a catalog of all the ways you reach would-be subscribers offline: with conference displays, packaging, collateral, magazine ads, white papers, even business cards. Now imagine there was a way to use each of these documents as a means of entry to your email list. There is a way – QR Codes. Create one that goes straight to your subscription page (or better yet, a mobile friendly subscription page that renders better on mobile devices and asks for less information).

5. Set up “Subscribe@domain.com”: You don’t have to go as slick as QR codes to lure mobile subscribers. Not everyone has a QR code reader installed on their smartphone, and it is not likely they will download one just to sign up for your email list. But everyone I’ve ever seen with a smartphone is highly skilled at firing off a quick email. So set up an email address just to accept subscriptions and promote that wherever your brand is in front of people grasping shiny iDevices. Couple this with the Proof of Concept tip above by actually printing out your newsletter and letting people sign up for it by sending an email, as the beer and wine shop around the corner from my office was doing yesterday. (It works – particularly when you tell customers they could have received 15% off that Cotes du Rhone by mentioning today’s email newsletter.)