Funny thing, this same question is on my Todo list to write about at some point.
It's far more complex than you would think. To me, good content is content that offers original thought and value to the community.
But my definition isn't the only one, I know a lot of people who are less concerned about "content" and more about trending, and distribution of wealth.
Some have zero concern about content and it is just a "fluff" thing, and nothing really matters on the blockchain. I haven't quite figured out what really matters in this case but it certainly isn't what anyone has to say.
Then you have some that have zero concern about the origin of content, it's just "sharing" it with the community, in this case, it's perfectly acceptable to get paid hundreds of dollars for this service.
Add in the argument "it's your stake to use how you want" to which I add "as long as it isn't someone else". While everyone has their own opinion about self-voting, delegation voting, bid bot voting, how do you build a sustainable system where you expect large investers to come in and participate when they cannot use their stake as they please? Yet on the other hand, how does Steem survive if everyone comes here buys stake and just votes themselves? At that point, it's just glorified mining with stake being the GPUs. We have a lot of work to go to define what we are as a community, what is acceptable, and how we are going to make this sustainable.
In the end, the simple fact is 85%+ of content on Steemit is embarrassing and doesn't deserve even $0.001. We as a community are still trying to figure out what is good content and what is acceptable. I think we will be figuring this out for a long time coming. While there is a financial incentive to every action, I don't think there will ever be an agreement.
RE: What is "good" content?