I'm not sure if there's been any discussion about it, and I can't really search it since it's such a common word, but why is by a tag? According to its wiki, it's for Creative Commons Attribution licenses, but it's also an extremely common word alongside the, of, a, with, etc. Given that there have been people uploading/tagging trying to write sentences of phrases with spaces, it's undoubtedly a mistag on some posts, falsely claiming such images are CC-BY when it's not. It doesn't look like very many images were uploaded by the artist themselves (at least as far as the site recognizes the uploader as the artist), making it impossible to tell if they're actually CC-BY, someone falsely or mistakenly saying it's CC-BY, or a mistagged word 'by'. But as long as it's a valid tag, it shouldn't be removed without knowing for sure it's incorrect.
What would be the best way to go about cleaning up and renaming the tag?