Writers beware: Em dashes are overused and misunderstood Today’s most overused punctuation—the em dash—is also its least understood. Learn how to use it. By Michael SebastianJuly 9, 2009 SHARE To read the full story, log in. Become a Ragan Insider member to read this article and all other archived content. Sign up today Already a member? Log in here. Learn more about Ragan Insider.