Don't worry about sending out too many marketing e-mails as long as you keep your content interesting, writes Michael Mothner, founder and CEO of Wpromote. "Yes, some people may unsubscribe," he writes. "But the impact you get from sending more e-mails far outweighs the loss of a few subscribers." Don't always feel the need to come up with fresh copy for e-mails, he writes, and consider sending a "remail" within 48 hours to people who didn't open an initial e-mail.