Email-friendly coupons require a few key components, and DSW nails them with this promotion.
1> It's simple, well designed and easy to forward on.
2> You're explicitly encouraged to share this with your friends.
3> It's a win-win for all participants. If you received this from a friend, you would never question their intentions for passing it on to you.
The Lesson: Keep your email coupons simple and encourage folks to pass them on.