Boost: I want other people to see this post.

Like/Favourite: I want the author to know that I value this post.

Bookmark: I want to remember / see follow ups to this post.

Unfollow: I don't want to see this person's posts unless someone else boosts them, or they mention to me.

Mute: I don't want to see this person's posts (temporarily or otherwise).

Block: I don't want that person to interact with my posts, or to see theirs.

@neil Hmm, must give bookmarking a try if it shows follow ups (immediate replies or all descendants?). Thanks for that tip.

@neil

Bookmarking does nothing to the flow of the post. It just lets you go back and see the post (and all that flowed to/from it) later, and that would be hard to do without bookmark because Mastodon has no default search.

@edavies