I've been involved in the Steemit Abuse channel on Slack and then on the new chat. So we've discussed a lot about plagiarism and I still tend to look for it, especially with photos that come in for the contest I run every week. If I find blatant plagiarism it's sent to the channel to be double checked, if it is plagiarism people tend to flag it and leave a comment on the article. For photos I tend to email the photographer through their portfolio website if it comes up with a reverse image search, asking them to confirm the steemit account.

Anyx created Cheetah to act as a helper for manual curators, so it leaves a comment and then anyx or whoever goes through and manually double checks it before it goes on to the 'next step' which might be leaving another comment or flagging or adding to a bot ban list.

It's not 100% fool proof, but we've caught a lot of them.