The general term for what Baremetrics is doing is called "content syndication" which is the fancy buzzword term for putting all your content on your own blog/domain first and then copying/importing it to other sites.

What makes Google not flip out and de-rank your content for duplication is two things:

1. There is a specific rel=canonical tag that sites can add into their headers pointing at the URL of the source article.

Medium's import tool (which is hidden at https://medium.com/p/import ) will add this header to the articles you import with it, pointing them back to your blog and not hurting you and maybe helping your SEO.

2. There is a notion of timeliness - that if you post on your blog first, wait for Google to index your content there and then post to a place where there isn't a rel=canonical option (like Quora, Tumblr, etc.)

If you're trying to convince someone else that they shouldn't put all their eggs in the Medium basket, point them to this article which is the "nuke it from orbit" article on the subject:

https://sendcheckit.com/blog/why-you-should-put-your-content...

The problem is that rel=canonical isn't always effective. So you can still get the SEO hit. Esp. if Google reads which site posted first what wrong (it happens)

When you import, you can choose a canonical source. So in Google's eyes, you're viewing it on Medium, but the "credit" goes to the original source.

How Google ranks the Medium post doesn't really matter in this case as that's not the point of it. Posting on Medium is about distribution to Medium readers.

It depends on how you move it over to Medium. If you just did a copy and paste, then it would obviously be marked as duplicated content. If you choose to import it from the URL of your Blog, then Medium will add a canonical link to the original article and Google will know which is the original document.