How Do I Target The People Who Didn't Open My Emails?

Joel asks how to target the people on his list who haven’t opened his emails. What’s the best strategy to get them to open the next email? Joel’s site is http://www.trackandtrain.org/. For my advice on starting an email, go to http://startanemaillist.com. Do you have a question about email marketing? Record it at http://www.askpat.com/. Today's sponsor is Freshbooks. Go to http://www.GetFreshBooks.com and enter "Ask Pat" for more information. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.