If you have ever anguished over the wording of an email subject line, we have a gift for you. It's a report from our friends at Return Path called, "The Art and Science of Effective Subject Lines."

Subject lines play an important role in the success - or failure - of an email campaign. Their first job is to get the email opened, but that isn't all. They also set an expectation in the mind of the recipient. If the email is opened and the creative isn't consistent with the subject line, the campaign will probably fail.

One hotly debated topic in the past has been the proper length of a subject line. Have you ever counted characters? We have. Does it matter? You'll find out.

What about discounts, humor and other provocative techniques? Get the report and find out the way to use them to improve your results.

We thank Return Path for this valuable resource. You can get the report here.