Tony Stubblebine, writing on Medium:
Today, Medium is launching a Mastodon instance at me.dm to help our authors, publications and readers find a home in the fediverse. Mastodon is an emerging force for good in social media and we are excited to join this community.
They launched their own instance rather than building ActivityPub into Medium itself. My instinct tells me this isn’t the right choice, but there’s value in having a variety of implementations. We’re in the early days and there’s plenty of room for experimentation.