So here's something that happens to me a lot.
- Filmmaker emails me with a question.
- I respond.
- Filmmaker takes my response as proof of fervent interest in his/her film and promptly adds me to an email list, pimping the film's screenings in cities where I do not live.
Sound familiar? If you're subscribing people to your mailing list without their permission, you fall on the Goofus side of the age-old Goofus/Gallant spectrum.
For me this happens just often enough to be annoying, but for a festival director who deals with thousands of films each year, it's a real problem. It only takes a few seconds to unsubscribe (if such a link is provided), but wading through an inbox filled with unsolicited (and usually irrelevant) news from well-meaning filmmakers robs festival staffers of many, many hours. Adding a programmer to your mailing list without their permission will accomplish the opposite of what you want - your film will get noticed, all right, but cast in a negative light.
Don't hurt your film's chances by spamming – there are better ways of getting your film noticed.
For more on email marketing best practices, check out the MailChimp blog. MailChimp is a terrific service. I use it for the Film Festival Secrets newsletter, to which you may subscribe – but only if you want to do so.