This post originally appeared on the American Express OPEN Forum, where Mashable regularly contributes articles about leveraging social media and technology in small business.

You’ve most likely had an e-mail newsletter for your company for much longer than you’ve had a presence on social media sites. But now that you do both, the two can go hand-in-hand, with e-mail creating an opportunity to extend your presence on social media sites, and social media sites providing a way to get more e-mail subscribers.

At the moment though, most marketers aren’t connecting the dots. According to a recent study published by eMarketer, 48% of marketers include “forward to a friend” features in their e-mails, but only 13% include features that make it easy to share content on social networks. Here’s a look at how to close the gap, and why it’s so important that you do.

Why Include Social Media in Your E-mail?

Just like a piece of Web content can “go viral” as people share it across social networks, your e-mail promotions can get a big boost by making it easy to share them.

A recent study by Marketing Sherpa concluded that simply including sharing buttons to an e-mail marketing campaign led to a “25% boost in reader interaction, and a surge in inbound traffic from social networking sites.” Moreover, huge gains were reported in traffic via social sites: 2,070% from LinkedIn (), 1,680% from Twitter (), and 1,351% from Facebook ().

How to Do It

Share buttons have become common on Web content, but they’re also easy to integrate into e-mails. If your e-mail consists of multiple articles, make sure each points to a page on the Web, and that your Facebook, Twitter, or LinkedIn share buttons are setup to share the URL of each respective article (note: you’ll want to stick to images and text links for your e-mail share buttons as opposed to JavaScript).

Beyond sharing articles though, make sure all of your e-mails include prominent links to your presence on various social sites. Calls to action in a sidebar or in the header like “Follow Us on Twitter” or “Become a Fan on Facebook” will help people connect with you on social sites and help build your audience on them.

Growth Strategies

Once you’ve integrated social media into your e-mails, be sure you’re cross promoting. There’s no harm in reminding your Twitter followers, Facebook fans, or LinkedIn contacts that you have an e-mail newsletter. And once they signup, they’re the ones most likely to share content with their own networks on social sites.

Beyond that, create compelling content that people want to share. While a good promotion might not be as viral as a funny YouTube () clip, your business’ fans will be more likely to spread the word if there’s a specific call to action. Moreover, create content that’s not necessarily a direct sell, but provides value to potential customers in the form of information that’s useful to them. Between good content and easy social media sharing options, your e-mail marketing can become a powerful weapon in growing your business.

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