Thread is not gonna be a standalone app but kind of like a sister app to Instagram, with Thread you can invite users or friends to automatically share their location, speed and battery life with members of another user’s closed friends list. (Why would I wanna share such sensitive informations with anyone)
The Thread app is said to currently be tested internally. The app according to the Verge
It not quite clear what instagram is trying to do but it seems like Facebook is really trying to merge all it services, Facebook messenger, instagram and whatsapp all to one messaging backend. Thereby making all their works internal and less external to the public.