Another platform that some people got excited for about 1yr ago. It was obviously not a direct clone of twitter in the same way mastodon is, but based on a japanese platform (misskey) and so just came from a different place with a whole bunch of features quite separate from the "mere microblogging" of mastodon.
It had flaws, sure, but there was genuine hope it'd become "the other platform".
But it was run like crap and fell apart and its flagship server is dead.