I like this campaign for several reasons:
1. It solves a real business problem by driving traffic into Macy's stores between now and Christmas (You must mail your letter to Santa from post boxes located inside the stores). The Office MaxElf Yourself campaign, by contrast, was fun but I'm not sure what, exactly, it did for business.
2. Believe fits the Macy's brand. Macy's, Christmas, Virginia, Santa Claus, it works.
3. It's viral. Turn yourself into Santa and send to it to a friend.
4. Finally, I like it because it rounds all three bases of the Trialogue. The brand speaks to the audience, the audience engages with the brand, and the audience is equipped to share with other audience members.
Spread the fire. GS