The good news is that the London company Alchemy Worx has solved one piece of the email puzzle for us—subject line length. According to their research, response rates are highest when the subject lines are in the 50-character range or 80-character range, but they fall in the middle when the length is 60 or 70 characters. To increase open rates, keep these magic numbers in mind next time before you click send.

Soliciting feedback from readers is an important part of a magazine’s research efforts. With a reader panel, a magazine has continual access to a group of readers who they can survey on various topics including past issues, future content and general opinions about the magazine. In addition to these editorial benefits, reader panels also provide an opportunity for advertisers to pose questions to your group of readers. Here are a few tips to help you manage your reader panel:

1. Keep it Short
Don’t be greedy with your panelists’ time. Limit each survey to 10 or fewer questions that can be answered in five minutes or less. Do not send a survey more than once a month or you risk panelist burnout. Remember these are volunteer readers so if you respect their time you are more likely to return a higher response rate.

2. Offer Incentives
Reward participation by giving readers something in exchange for their participation. Select incentives that are appropriate for your audience. Gift cards are a practical option for most groups.

3. Experiment with A/B Test
Segment your panel into two groups and try different subject lines, day of the week, time of day and personalization. Analyze the results to determine the optimal combination for the most successful survey.

The Custom Publishing Council (note: Hammock is a founding member) has just conducted a survey called, “Characteristics Study: A Look at the Volume and Type of Custom Publications in America” that indicates custom publishing is thriving. According to the survey, in 2007 a record number of marketers used custom publishing solutions to promote their products and brands – with impressive results. Other industry reports show that spending on alternative media jumped 22%, with more advertisers seeking out new channels. Custom publishing can be expected to grow even more in 2008 with the increase in Internet distribution of content and creative new media solutions.

[After the jump, view statistics and other highlights from the Custom Publications in America survey.]