Oh, e-mail! For many individuals and organizations, e-mail has transformed both the quantity and quality of human communication. Simultaneously intimate and public, e-mail is a daily symbol of the potential and danger that technology promises. To some, e-mail is a simple and sublime medium to communicate in the modern world. To others — and often the same people — it is a reviled and bottomless pit of unwanted spam that infuriates and frustrates.
Nonprofit organizations of all sizes and budgets are exploring how to integrate e-mail into a comprehensive communications and fundraising strategy. Some are far along the road of doing so; others are just starting out. This article provides an overview of why and how to use e-mail in your fundraising program.

Michael Stein is really good at this stuff and knows what he is talking about. The core of the advise is about strategies to use email as a relationship tool and communications pipeline. You would not ignore body language if you were talking with someone nor would you not pay attention to feedback of pauses and silence on a phone call. It is possible to use email effectively and monitor not only direct reactions to your message via responses but to use tools to monitor the silent messages (open rates, subscribe rates, etc. It is a good article worth reading.