Only if you do so very carefully, and after reading this must-read How to Make Prospects Tune Out Without Trying. The risk is that as few as 0.5% of mass e-mails may be read, vs. upwards of 95% of a large postcard mailing. Choosing whether to mass-email also depends on your organization, its size, and its constituency. If you are a small local organization such as a theatre or a church, with close-knit prospects who admire your operation, they may welcome your emails. If you are a large organization with a diverse membership, you will encounter many respondents who aren’t pleased that you add to the clutter in their in-boxes. In general, email blasts (especially automated ones) will be detrimental to your program.