Technical features are one thing. Not familiar with any organized work, but that doesn't mean there isn't any. But the other area which would go a very long way to addressing user concerns is explicit public data use and privacy terms. Thinking of an opt-in/out-out framework that gives users explicit control over their content and personal data. Such frameworks, particularly in the EU, are now common for internet services. If we want open social to work, we should do it here too.
@mastodonmigration @evan great point. Mastodon already has a number of these built in which is a good start.