I totally agree.
I think the key to member retention is interactivity. If your site is only two demensional and passive, then the member will do their deed within a few minutes of signing up with you, and then cancel, but if you can pull in that member by the site interacting with them, then that is where you get the retention. Everyone has photos, everyone has videos, everyone has live feeds, but those that go outside of the box, that makes all of the difference in the world.
Something else to keep in mind is that we have almost 100% retainment of all of our clients, so the content works, or they would all cancel. There is a lot to be said with interactivity.
That's why our new suite of multiplayer games are going to rock!