Activation Emails
Transactional in nature but promotional in practice, activation emails hit the email marketing sweet spot. Use emails like this to get things done.
Gazelle
“Click that button to activate your account, but while you’re at it, check us out of Facebook and Twitter as well.”
Keeping users engaged on multiple channels is a great way to market to them passively. Then, when they are in need of your service, you are top-of-mind.
Moz
Moz is a great at branding. The blog, the community, the conference, the videos … it’s all part of what makes Moz a household name. It’s no surprise then that their activation email is consistent with the rest of that experience. From the copy to the design, it sets the expectation that this is going to be fun.
UserVoice
At their core, activation emails require that users take action. Depending on your product or service, it may be best to take the UserVoice approach: a dead-simple, plain-text email.