On the night of March 9, a mysterious email from DonorsChoose.org, the nonprofit that connects schools in need with donors, found its way into the inboxes of a half-million teachers around the country. The email was intentionally vague, simply telling the teachers that DonorsChoose.org had something big planned for March 10 and to follow the hashtag #BestSchoolDay for more information.

"Even that night, we were seeing teachers using that hashtag on Twitter. That really created a huge momentum for the day. It got teachers really excited," said Director of Email Marketing at DonorsChoose.org, Morgan Kazan.

Social conversations built quickly in anticipation of the announcement, delivered by DonorsChoose.org board member and #BestSchoolDay originator Stephen Colbert on CBS This Morning. Colbert announced that he and 57 other celebrity and business leaders, including Ashton Kutcher, Serena Williams, Samuel L. Jackson and Twitter Co-Founder Biz Stone, funded over 11,000 classrooms in 47 different states.

Social media exploded and the hashtag promotion was critical to igniting that success. #BestSchoolDay eventually became a Twitter Moment and remained a trending topic on Facebook throughout March 10.

"A huge part of that was because we emailed teachers to go crazy with this hashtag the day before," said Kazan. "This was the first time that we've ever really pushed a hashtag and pointed people to social through email. We really weren't sure what was going to happen."

The personal relationship formed between donors and teachers is critical to the organization's success and email has always played a critical role. Since its founding 16 years ago, the site has been host to more than 740,000 projects, engaging over 2 million donors.

DonorsChoose.org uses Marketing Cloud to automate personalized customer journeys that keep its donors and teachers coming back for more. On a normal day all donors receive a dollar-for-dollar report of how their money was spent and a personalized thank-you from that specific classroom. During the #BestSchoolDay drive, the typical emails were augmented with special content, including personalized messages to the 11,000 teachers that had a project funded from the original 58 donors.

For example, Samuel L. Jackson, along with several other donors, recorded a video explaining why he funded his hometown of Chattanooga. The videos were sent to the teachers, prompting numerous reposts on social media.

Later in the day the DonorsChoose.org team sent an additional email to all their teachers (and donors) to update them on the progress of the campaign.

To add to the excitement, two anonymous donors offered a $1.5 million, site-wide match that helped keep the #BestSchoolDay momentum going for weeks. DonorsChoose.org made its donor base aware of the match offer through an email that also included highlights from the #BestSchoolDay campaign.

"I think we emailed probably close to a million of our donors to let them know about this," said Kazan.

Coupled with the continued success on social media platforms, the momentum drove 20,000 new donors to the website to discover how they could become a part of 2016's #BestSchoolDay. This translated into 5,000 more funded projects in the week following March 10.

The incredible outcome of 2016's #BestSchoolDay has left DonorsChoose.org inspired to start the early planning stages of 2017's #BestSchoolDay. Though it's too early to say exactly what that day will look like email will play an integral role.

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