You collect data about how many times a person opens an email and, of course, how many emails they get. I would like to order and segment my subscriber list by participation level
opens / emails received * 100
for two reasons:
1) to reward those that are active
2) to entice or remove those that are not active.
That's a nice idea, and we are definitely looking at some ways of providing more information about the actions of particular subscribers.
Right now you can create segments based on who has or has not opened specified campaigns, which might get you towards what you are after.