[bolding added.]
This is the key argument against Peterson's insistence that his personal blog isn't really 'published' material, therefore it's not plagiarism. His blog entries contain many, many instances of stealing the intellectual property of other authors. Just because he thinks it's okay to steal their material because he's not really 'publishing' it doesn't mean it's not theft of intellectual property.
In fact, the institutions who legitimately publish works by the people he steals from uniformly define what he is doing on his blog as theft of intellectual property. Everyone is in agreement, from patheos to BYU to Wikipedia to every source Peterson steals from: Plagiarism is defined is stealing someone else's work, regardless of where you put it.
Additionally, this thread documents a multitude of Peterson's plagiarized publications across more than just his blog. It documents his plagiarisms at the Deseret News, the LDS meridian and lifestyle magazines, and even in the Interpreter itself.