The Objective: With over a million and half online users, the company knows that referrals from current customers are a big contributor to the addition of new accounts and a major contributor to its overall growth. With that in mind, we researched ways to accelerate referrals and ultimately decided to test enhancing one of its most successful channels (email) with social media capabilities.

The Program: Mint.com introduced three social "treatments" into its email program. All three programs asked email recipients to share their positive experience by referring friends. The really innovative piece came in the way Mint.com tested the various offers. Once recipients clicked the link to share their Mint.com experience, they were presented with three different "social motivators" to share. The first offered the opportunity to win a "Minty Green" iPod Nano once three of their friends became Mint.com users.

The second offered exclusive access to the Mint.com content (in this case access to its Financial Fitness beta program) in return for referring three new users. The third served as a control group, offering no reward. We tested all three offers against a smaller segment of the list and found that the exclusive beta access "treatment" was the clear favorite.. As a result, Mint.com deployed the winning campaign for the balance of its broader email target segment.

The Results: When looking at the results from socialized email programs, I think it is critical to focus on two areas, reach and conversion.

Reach: Socializing email, at its core, is about extending the reach of your current email programs. If you can motivate your customers to share on your behalf, you can grow your email file, subscription lists and ultimately your customer base exponentially.

Conversions: The other basic premise of socialized email is that our social networks are filled with friends with similar likes and interests. If I fit the ideal Mint.com customer profile, then it is likely that several members of my social graph (the people in my personal address book, Facebook friends, Twitter followers, etc.) also fit the profile.

Even more important is the added credibility brands get when consumers are introduced to their offers from within their social network. On the social Web, friends trust friends. It is this peer advocacy that results in increased conversions within socialized marketing programs.

If you have been having trouble putting real numbers to these two assumptions within your business, have a look at Mint.com's results.

Social Accelerating Reach and Conversion

The winning "exclusive access" email was opened by 48% of those mailed. Of those, over 10% became "Influencers" for the Mint.com brand by sharing the invitation with an average of five friends each, significantly expanding the program's reach.

The increase in reach aside, these invitations generated an unprecedented 61% click-through rate for friends viewing the invitation. More importantly for Mint.com's bottom line, every 2.6 invite clicks led to one friend becoming a new Mint.com user.

So, by having 10% of those mailed becoming influencers and sharing an average of five invitations with their friends, Mint.com was able to add more than 8,000 new users, which was a significant boost in the conversion rate over its typical, un-socialized and already successful email campaigns!

The key takeaway here is that social channels, combined with the right email strategy and sharing technology, can have a near-term impact on online conversions. I suggest you get busy testing email and social in your business or risk your customers becoming influencers for your competition.