Steemit - Steem - nearly one to one match. I was thinking more about apps running on a shared blockchains. Like for example many apps currently running on the Ethereum blockchain and probably many more in the future running on EOS, NEO, Cardano...
Now I could imagine a next generation Steemit / Facebook accepting/emitting tokens on various blockchains, based on user's preference. Such new platform could bring many different blockchain
users together. If I'm correct then Cardano is working on some kind of eco system enabling pear to pear exchanges of tokens between blockchains.