me.dm is a Mastodon server where people with Medium accounts have access. I don't know if they can authenticate with Medium itself or if they just have some way to request a Mastodon account.
medium.com does not interoperate with the Fediverse and me.dm holds separate content.
@pluralistic I appreciate that your content is open and on multiple services. I am enjoying it here and on your own site and don't mind that you parallel publish on medium, your strategy is up to you and I'm not contributing even a fraction of what you are doing for the web and the open internet in general. But saying that medium is not a content silo and that it's federating is factually wrong unless I'm missing something.