RE: When is sharing another contributor's content appropriate?

It is common courtesy to ask permission. But most won't and don't care

The most common issue is content being used without permission. Once we have a way to directly communicate with each other , a simple "May I use your image in my post" would help stop many conflicts. In some cases with original photos the user may not want it used and so would decline.

The problem is most won't even ask they just do. The way content is shared on the internet, is for the most part not frowned upon at all, so users have become accustomed to this and think nothing of it.

Because steemit is a way of making money things become more complicated. Users with original content need a way to inform users it is not ok to use anything they post unless permission is granted. Or the community could take care of this collectively. There are a few ways this could be achieved depending on how far the platform is willing to go with implementations.

In a virtual world, i have been involved with for many years, they introduced a "Peer Review" system. Users submit their creation it then goes into "Peer Review" The content is not visible to the public but only to the users participating in peer review. The content must get x-amount of votes before it becomes public. Peer review is based on a reward system for users that participate. This dramatically reduced the amount of copyrighted material.

The Peer Review system works very well because it is incentivised. Also, it helps maintain a Good tier level which is the equivalent to the "Reputation System" on steemit. There are many more layers to this system, I just mentioned an overview.

I am not saying this exact model would work but something along those lines could help stamp out a lot of the abuse.