I certainly respect John's opinion, and I agree 80%, but I also believe that a big part of your list maintenance work involves relationship building so I sometimes think it's important to meet them a little more than half way and give some good stuff once in a while.

Another thing about lists I've been playing with is the idea of setting time limits. Here is what I mean. It's easy for subscribers to say, "Hey, I'll read that later" and move on to something else. On a couple of my lists I've use a title such as, "12 hour incredible download". Of course it's important to give them an incredible download or it falls apart. Having said that, I've used this with an annoyingly unresponsive list to move it from an 18% open rate to over 30%, which is in my mind quite significant.

This gives them a reason to open your emails NOW. Sure, I get a couple complaints from people who say they didn't check their email until a day later or so--but overall, doing this once in a while seems to have a positive impact. Still testing, but it seems to work.