Here is what we know about it so far:

• It will most likely be called Threads.
• It is not known what domain it will use for usernames.
• In mockup screenshots, a user replies to someone using an @mastodon.social handle, it’s very likely that they will federate.
• It will be side app of Instagram. It’s not clear how much of the new network will be baked into the main app.
• Your username and verification status will carry over, so early adopters won’t have an advantage for their preferred username.
• Your followers will not carry over but there will be an easy way to pick and follow people on your Instagram list.

Personal observations:

• Many people that I talked to about it think that this will be Meta’s attempt at an “EEE”.
• Some Mastodon instance admins that I chatted about it say that Meta will “likely attempt to pull their user data”, and they “will defederate immediately”.