"Surprise and delight your subscribers!" It's a phrase email marketers read and hear often. A popular option for brands to do just that is a birthday email-an automated email sent on the subscribers' birthday. But what makes an effective birthday email? I celebrated my birthday this month-and my inbox was chock-full of emails from brands helping me celebrate. But there were a few that stood out. Here are the five birthday emails I loved the most and what tactics you can steal from them to really surprise and delight your subscribers on their birthday.