Alan Kay said it: "Simple things should be simple, complex things should be possible."
For example, something like Twitter fails massively here. It's easy to use as a novice, but there's no progression (I know that sounds like a concept from games, but it seems applicable). I want to be able to see who, of all the users I've seen, listed, followed, is active these days. I want to be able to draw on other people's list of follows to extract suggestions of who might be good to follow & is actively tweeting (not dumb automatic suggestions, please).
It would be so amazing to be able to "bin" Twitter users (across all of my lists, follows etc.) by how active they are. So the excessively chatty ones can be browsed when I have time, and the ones that post almost never—well, when they do, I see it.
However it is important to remember that if your product is successful the vast majority of your users will not be beginners and so you need to make sure their experience is good.