Sarah Jeong of Motherboard says Mastodon is a "kinder, nicer, decentralized open source version of Twitter." I hope she's right! (I'm frauenfelder at Mastodon.cloud.)
Snip:
Privacy settings are more flexible than they are on Twitter—privacy is set on a per-post basis, a little similar to how it is on Facebook.
I could make it so all of my posts are private by default, but I don't have to choose between having a public or a private account.
The really interesting nuance here is between "Public" and "Unlisted." An unlisted post is viewable to the public, but it doesn't post to the local or federated timelines.