> Replacing Twitter -- Part of the appeal of Twitter is that it __is__ centralized. I can find and discover arbitrary tweets or threads by popular people all in one place. On Mastadon, I, presumably, have to explore several different servers in order to find the people I want to follow, which throws up barriers against something Twitter does really well.

Mastadon is a federated platform using the OStatus protocol, so you an interact with anyone on any server using that protocol (Mastadon, GNU social, etc.). That means you can follow anyone, boost (re-tweet) any message, and even see a feed from the whole fediverse.

Now, it is possible to block some servers from your server and vice versa, but this just allows you to find a community that shares the same values as you or even setup a server of your own if you can't find a server you like.