Email marketing has gone through a sea change since it first became a viable marketing channel in the 1990s. Much of it has been for the good, but a few bad practices persist from those wild early days.

The good: Marketers are designing more relevant, targeted messages that can be read on any platform, browser or email client, and are giving subscribers more control over the messages they get.

The not-good: Some marketers haven't poked their heads out of their cubicles long enough to see that time has marched on and left their opt-out blast mentality in the dust. They're still laboring under the delusion that email is just digital direct mail.

What's holding them back? They're clinging to a few myths about email marketing that I'd like to dispel here and now.