by Adam T. Sutton, Senior Reporter

Looking over the dozens of case studies and how-to articles we published in our Email Marketing newsletter this year, many of the most popular focused on improving more than just response. Many teams also improved efficiency.

"Value" was the name of the game this year, and email marketers worked day and night to prove their programs were ROI powerhouses. Whether you're stuck with a tight budget, or you want to improve your email ROI, check out this year's top articles to help get you there.

Auto-results from triggered emails

Automated emails are like robots. They work 24-hours-a-day, long after you've gone home. Setting them up and improving them is hardly "automatic," but an established campaign can drive results without eating many resources.

Many marketers found triggered emails to be effective sales drivers in 2011. We featured a litany of companies that used them last year. Here are three case studies that show how triggers can improve referrals, remarketing and lead nurturing.

Email Marketing: Triggered email nets 75% of referral program signups - See how this consumer electronics company sent a triggered message to new customers that successfully encouraged them to refer contacts.

Remarketing Emails: How JetBlue's automated triggers get 1,640% more revenue-per-email than promotional emails - See how this 2012 Email Awards Best-in-Show winner created a system of four triggered messages that generated more revenue-per-email-sent than its promotional emails.

Email Marketing: Anti-newsletter strategy nurtures $1.5 million in leads in 4 months at Citrix - See how the 2012 Email Awards B2B Best-in-Show winner stopped sending an email newsletter, started sending targeted content, and nurtured more than $1.5 million in leads in four months.

List Growth: Boost volume to boost results

The quality of subscribers in your database is extremely important -- but it isn't everything. Even if you had the best subscribers in the world, it would not help your marketing if you only had a handful. Sometimes, you simply need more names. These three case studies show how marketing teams found more of the right people for their lists.

Growing Email Lists with Social Media: KFC's Facebook tool adds subscribers - Check out why KFC added an email registration form to its Facebook profile and the impact it had on the company's email list. Also, see why you should track social influencers in your database.

List Growth Tactics: How Kodak added 33% more email subscribers and 53% more YouTube followers - Kodak overhauled its capture page, added more calls-to-action, and updated its welcome series to grab 33% more email subscribers. You'll also find out how the team integrated its social media channels and grew its audience in the networks.

Mobile Drives Email List Growth: How to use SMS and relevant content to add opt-ins - See how Scotts Miracle-Gro combined print pamphlets, SMS short codes, sports marketing and email to add more subscribers. Of people who requested content, 40% also subscribed to the company's emails.

Reactivate, Reuse and Remarket

Some marketers in 2011 were tired of wasting resources on prospects who never converted. Their teams launched campaigns to reactivate deadbeat subscribers and remarket to visitors who left their companies' websites.

Email List Reactivation Incentives: Gift cards vs. whitepaper vs. nothing - Cisco tested a reactivation campaign with very interesting results.

Lead Nurturing: Old names yield 37% of customers - Software provider Infusionsoft pulled more value from its database by targeting long-term, low-converting subscribers in a campaign that offered quality content.

Shopping Cart Recovery: Triggered emails recapture 29% of abandoned carts - A great example of why you should test expanding your shopping-cart-abandonment emails into a three-message series.

Useful links related to this article

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Email Marketing Summit 2011: 7 takeaways to improve results

Email Trends 2010: Improve relevance, test emerging channels

Email Trends 2010: Proven tactics and test ideas