Remember that you can also create threads on Twitter. So, hence the name. And according to some media, screenshots show interaction with Mastodon users. I don't think it'll be a threat for Lemmy/Kbin, PeerTube, Funkwhale or other services, but if any danger or threat, it would be for Mastodon, Pleroma, Misskey, Akkoma, Calckey, and maybe Friendica and Pixelfed. But it's too early to create facts. I need tangible or visible evidences, not speculations.