A great many promotional messages to consumers do not get opened. Why? Because the subject line tells the reader, "There is probably nothing that you want to hear about in this e-mail." In other words, the subject line says that the e-mail content will not be relevant to the reader's current needs or interests. If you are sending an identical message to one million of your existing customers, it is unlikely that you can create copy or an offer that will interest all, or even half of them. There is just too much clutter in everyone's e-mail inbox.