Each month Mozilla sends a newsletter to an audience of approximately 3.4 million recipients called Firefox & You. Recipients opt in to receive the newsletter, which provides tips for the Firefox browser and OS, along with other updates from Mozilla.

Once per year, we send one email in late December to this list asking recipients to make a donation to Mozilla. Last year that email raised $141,927. This year it will be sent on December 30th. We get one shot at appealing to this audience, so we want to do some work ahead of time to dial-in the message. We’ll also be trying some new strategies this year that I know work well for other organizations.

Subject line testing. Subject lines can make a significant difference in open and response to donation appeals, so we tested four separate subject lines sent to four small segments of the Firefox & You list. Here are the results from those emails sent December 19th:

Subject line B won with a 34.4% open rate and 1.8% click through rate (CTR): We are only sending you one email. We’ll be using it for the full list send on December 30th.

New call-out box. For the first time we designed the message template with a call-out box. You’ve probably seen them before in email messages from other nonprofits. Here’s what this year’s message looks like with the new call-out box looks like:

We assigned a unique tracking code to each of the three clickable elements in the email: 1) The new call-out box; 2) the first text-based link in graph five; and 3) the second text-based link near the bottom of the email. Here is how donations were distributed across these elements:

The call-out box is doing its job – grabbing just under 2X the revenue as the first text link in the email message body. So far, the data supports the decision to add it. It’s true that some portion of recipients who clicked the call-out box would have clicked on the first text link absent the box, but probably not 100% of them. It gets attention, and that’s what it’s there for.

Here is the combined revenue data from all the subject line tests messages:

Localization. In addition to the 3.4 million recipients of the English version, for the first time we are also sending this message to Firefox & You subscribers in French, German, and Portuguese (Brazil). These three locales represent an additional three to four hundred thousand recipients. I’m excited to see how these Mozilla supporters respond to the year-end fundraising campaign.