Social media is proving to be a highly valuable marketing channel in its own right, driving greater engagement and quantifiable results. For example, according to research recently published on Social Commerce Today, people are 51% more likely to make a purchase after clicking on a “Like” button, and Facebook fans who do purchase spend 117% more than non-fans. Facebook fans are also 28% more likely to repurchase, suggesting that social engagement helps drive loyalty as well.

If someone is more likely to purchase, purchase more often, and spend more as a result of social media, it is a reflection of deeper investment with your brand and interest in your products. The causality is unclear: are engagement and purchase metrics higher as a result of social engagement, or are the people who are already buying more and more often the same people likely to engage with your brand socially? Ultimately it doesn’t matter once marketers understand that social fans and followers are among the most engaged audience. These are the people you want to involve in as many of your marketing efforts and channels as possible.

Moving these people into your email subscription list, then, makes perfect strategic sense. Since they level of engagement among social fans is strong enough to move the needle on commerce metrics, it stands to reason that the softer ask of “Subscribe to our email” should enjoy a similar lift among this population. Recruit engaged prospects and customers to your email list and your email metrics should see a nice uptick as well.

Here are some ways to grow your email list with social media:

1. Add a subscription or contact form to your Facebook Fan Page. DM News recently reported that only 10% of brands on Facebook allow their fans a way to opt into the brand’s email list. While opt-in is not quite an incentive, it’s a necessary first step for harvesting that social engagement into your email program. Services like pagemodo and TabSite make it easy (and free!) to add customized tabs to your Facebook page, including graphics-rich welcome pages, contact forms that allow you to capture email addresses (all CAN-SPAM rules apply even in Facebook) and even embed email subscription forms and iFrame content that populate your email list directly.

2. Use unique social and email promotions to encourage pan-channel participation. Creating promotions unique to your social channels and email subscribers is a great way to drive engagement within the channel, and with your brand. For example, say you are an association promoting your big annual conference. During the months leading up to the show you launch “Wednesday Wake-Up Call,” a promotion where you offer something of value to a limited number of participants. It might be a room upgrade at the conference hotel worth $100 that you’re selling for $25, or a free shoe shine at the hotel valet during the attendee’s stay. You limit these to the first 10 participants and push them out every Wednesday morning through Facebook, Twitter and email. Soon your audience will grow to expect these promotions, and if they’re compelling enough will even anticipate them. But because of their limited availability, timing is important. Social channels offer immediacy, but not everybody is on Facebook or Twitter all the time. Continue to remind your audience that you only promote Wednesday Wake-Up Call on Facebook, Twitter and by Email, and that to increase their chances of seeing an offer quickly, they should fan, follow and subscribe in as many places as possible.

3. Use a Like Gate to draw more Facebook fans into your email funnel. Now that you have an opt-in form on your Facebook Fan page, and some engaging promotions to encourage your Facebook fans to subscribe to your email list as well, the work you put into acquiring more Facebook fans yields greater pan-channel dividends. A “Like Gate” is a feature on Facebook that makes certain content on your Facebook page only available to people who are fans. The more compelling the content, the greater reason someone has to become a Facebook fan. Maybe it’s a $100 discount off an upcoming conference, or a free polo shirt when they check-in at the conference. It might also be the opportunity to enter a contest, vote in a competition, or contribute questions in advance for the Q&A session following a keynote speaker’s presentation. Drive up the quantity of qualified fans and you have a broader base of engaged customers to pull into your email list over time.

4. Test Facebook Ads to find all new prospects. One of the reasons that Google AdWords became so popular was its ease of implementation for marketers. Text is a lot easier to create than flash movies or animated gifs, and Google’s interface allows the marketer to control the entire campaign setup and management, monitoring performance, targeting effectiveness and budget. Facebook Ads operates much the same way, but Facebook also makes it very easy to integrate images into the ads, and target extremely narrowly. Even if yours is a brand that does very little advertising, Facebook Ads may still have a place in your marketing programs. Target ads by interest, location or demographics, and ensure you’re reaching prospects by limiting your ad only to people who are not yet fans of your page. For narrower targeting, you can also serve ads to people who are fans of another page you identify (a competitor or partner, for example) or to the friends of your page’s fans. Facebook Ads are pay-per-click, so target the ad copy as narrowly as possible, ensuring that it only appeals to your precise target. “Free room upgrade at the Hyatt in Miami!” will cost you a lot of unqualified clicks, while “Free room upgrade at Miami Hyatt for IndustryCon Attendees” will limit the clicks to the audience you’re interested in reaching. Put the promotion behind a Like Gate (see #3 above) so that your ads drive new fans, and then use your existing programs for converting fans to subscribers (see #1 and #2 above) to double the ROI from your Facebook Ads.