kbin has a tag view - you can click on it, and it will display content from the fediverse, merged with Mastodon posts and other microblogs. The type of content found there depends on the instance and any relay connections. Personally, I've never been a fan of the chaos in large Mastodon instances.
It's something I'll be working on in the future. I'm focused on integrations with various platforms and convenient browsing of multimedia content coming from them. Currently, it's done provisionally and is not the final solution.
I won't comment on the rest because I've always hated the Twitter format. But I know that there are many people who find it appealing. Mastodon didn't suit me either, despite several attempts to use it.