Here’s a Valentine’s related email marketing case study from Marketing Sherpa about how IdeaArt sent a campaign to a huge list of subscribers, and got so-so results. Then they decided to send a follow-up campaign to "people who opened but did not click." The new campaign went to a list that was 8 times smaller, but got more than double the sales.
The idea of "remailing" is discussed in the article. Some people send "remails" to "people who opened." Or, to "people who did not open." If you want to be able to do that with your MailChimp account, look into our AIM Reports.