If your brand is looking for new ways to promote your twitter presence in email, look no further than @CallawayGolf 's email and what they do towards the footer of their email.
The key takeaways here:
Make it more than just about your main twitter handle.
Make it human by including the avatars of those that are featured.
Lead the subscriber with a clear and conspicuous "follow" button.
Carve out some significant email real estate for something that you are good at and are passionate about. If anything, it could increase revenue.
Make sure you can track where your followers are coming from and ensure that you welcome them appropriately.
Congrats to @CallawayGolf for making something different in their emails, rather than just the same old social icon push....