The first rule of direct-mail letter writing (and writing headlines, too)…

 …is NEVER start with a question that can be answered "no." 

As in, for example, this from the subject line of an Amazon email

Ever wonder if your reviews are getting noticed?

In fact [Pro Tip] starting with any kind of question at all is generally a bad idea.

(Except on this blog, of course. But then I'm not selling anything.)