The Cardinal Sin

Okay, maybe it's not the worst, but it's pretty bad: your organization provides a contact email on your web site, in an email, or on a brochure, but you don't reply to email sent to the address.

Friends, Romans, arts organizations: don't do this.

It's like lying to your patrons, by implying that the email address is monitored. Your patrons buy tickets and make donations to your organization. They are people you want to keep happy. If they have a question or comment or even a complaint, they deserve an answer from you.

You undermine their trust by not doing this, and you might piss them off enough that they reduce their donations or ticket purchases, or stop entirely. (An organization I donated to for years and years didn't respond to two direct communications I sent them, one of which included a donation. My third letter got a perfunctory apology from its executive director, the addressee of the second letter, and I have not donated since.)

So: if you have a contact email, make sure you read and reply to comments from people who take the time to contact you. It's a great way to earn the trust of the people who care about your organization.