Yesterday at #indieweb summit, someone - I think @aaronpk@twitter.com - mentioned that one of the big differences between IndieWeb initiatives and ActivityPub is that IndieWeb is made up of simple building blocks you can pick and choose while ActivityPub frontloads a lot of complex work.
This is a sentiment I very much agree with and it’s unfortunate that the main reason Mastodon switched from OStatus (which is very IndieWeb-esque) is because it made it slightly less inconvenient to pretend to have private posts. Which aren’t even implemented that well.