April Challenge: Email Survey Results

One of the first steps of my April Challenge was to send two survey emails. The first was to users who paid for the premium service since the beginning of the year. The second group was users who signed up for the trial, but gave up and haven't returned to the site in at least two weeks. The emails went out a week ago. These are the results.
Paying Users
There were 410 people in this group.  They all received the same email.
Subject: PlanbookEdu Feedback - Win a $25 Amazon.com Gift Card
Text:

Hi {email},Earlier this year you signed up for PlanbookEdu.com. We hope that your experience with the program has been positive and we've made your lesson planning easier.
We would like to know what you feel has been the most valuable benefit of using PlanbookEdu.
Simply reply to this email with your feedback and you will be entered in a drawing to win a $25 Amazon.com gift card.
Thanks,PlanbookEdu Support800-378-7131planbookedu.comfacebook.com/planbookedu

Response
Of the 410 people emailed 46 (~11%) responded. The responses were overwhelmingly positive.  21 used the word "love" at some point. To parse the data I read and responded to every one. In the process I kept a list of benefits and would add a tick anytime one was mentioned.  By the end I had pretty good idea what everyone like the best.
I'm going to use this information to revise some of the wording on the homepage to better appeal to the benefits that really stood out.
Also, even though I didn't ask for it, many users suggested features they'd like to see.  There were two that clearly stood out. They were already near the top of my list of things to add, so this justified my belief that they are high priority items.
Users That Gave Up
There were 977 people in this group.  They all received the same email.
Subject: PlanbookEdu Feedback - Win a $25 Amazon.com Gift Card
Text:

Hi {email},Earlier this year you tried out PlanbookEdu.com. We noticed that you haven't returned lately and would like to find out why.
We are constantly trying to improve our service and any feedback you'd like to provide would be extremely helpful. Was it to complicated? Did you find a better solution?
Simply reply to this email with your feedback and you will be entered in a drawing to win a $25 Amazon.com gift card.
Thanks,PlanbookEdu Support800-378-7131planbookedu.comfacebook.com/planbookedu

Response
The response to this email wasn't nearly as good. I guess this can be expected since this group has already given up on the site they probably don't care enough to response. The chance at a $25 Amazon.com gift card wasn't motivating enough.
There were 25 responses, approximately 2.5%. The responses from the first group generally fell into 5-6 main areas with two benefits really standing out. This group had responses all over the map. The most common being that they haven't had time to "play with it".
Combining the people who haven't had time and those that were confused (2 people wrote that) makes me think I need to do more to ease the learning curve. I've already done a lot to make the transition easy, but there is clearly more that can be done here.
The Contest
Since responses have pretty much stopped coming in I'll be picking winners to the contest in the next day or two. Here's my completely scientific and fair process:

  1. Go to Gmail and do a search that will filter out just responses for that group.
  2. Get the total count for responses
  3. Go to random.org and generate a "true random number" between 1 and the total number of responses.
  4. Count down in Gmail until I hit the random number.

What I'll Do Different Next Time
The first thing I'd change is have different subjects for the two groups. This would have made it easier to separate the responses. Plus, I think a better subject would have gotten more responses for the group of people who gave up.
I thought very long about giving a guaranteed reward.  Something like a $5 Amazon.com gift card just for responding. I may do this for the group that gave up, rolling out smaller email batches at a time until I hit some budget limit, say $150.