Many actors on the web are not good citizens. This is particularly true with so-called "viral" content material that spreads very quickly as hundreds or thousands of people share it.
When that information travels around network, people often fail to link to sources, or hide them altogether. The FaceBook directive, "Copy and Paste, Don't Share" is an example.
This phrase encourages people to separate content from source and date, as a way of preserving it against censorship - but what is more likely is that the content was designed to be scanned and shared quickly, without fact-checking. Be very sure you trust content before copy-and-pastes to your friends.
- from Web Literacy for Student Fact Checkers by Mike Caulfield, https://mikecaulfield.files.wordpress.com/2017/01/webstrategiesforfact-c...