Two things that would make Mastodon even better:

1) More instances that are clearly *for* something (e.g. photography, Doctor Who, Linux etc.) - I'm thinking like the old Usenet newsgroups.

2) A way to filter the federated timeline to only show the instances you are interested in. https://github.com/tootsuite/mastodon/issues/423 looks like an option, but really anything that manages the firehose would be :ok_hand: