@tchauhan @aral a starting point:
Imagine if you could comment on Instagram from Twitter, or like a YouTube video from Facebook or Reddit.
This is what the Fediverse allows with its counterparts (Pixelfed for photo sharing, Mastodon and other platforms like Misskey or Akkoma for microblogs, PeerTube for videos, Friendica in place of Facebook, Lemmy and kbin for link sharing.)