Resourceful Mommy criticizes instances where curators have curated content unethically.  There's a fine line between ethical and unethical curation and this post highlights a few examples of where it has been crossed.  For example, even if you cite the source, which source you cite is important:

It is not okay to list Pinterest.com as the source for the content you are sharing just as you would not list Google.com as a source.  Imagine getting to the Bibliography of your college term paper and listing “Library” and the address where the building is located.  That is precisely what these authors did.