When presented with too many options, it's easy to avoid change. A fork in the road is easy when choosing between two paths. But if that path suddenly branches in 5 different directions, you stop. You check the map. You might even pause for a rest when you'd prefer making progress.
Your customers prefer progress too. So when helping them choose you, keep it simple. Make sure every marketing piece offers just one decision and make it between two options. They either return your email or they don't. It's their choice.
You have the power to give them that choice, to make it easy. They'll love you for putting them in control. The more they love you, the more they choose you.