Jack Dorsey’s other social platform has been in the making for some years (2019) but is soon to go into beta testing. If of interest sign up here:
https://bsky.app/

It’s not a blockchain nor does it use a blockchain. Blockchain – leading the way in security and trust (and lots of other good stuff). It’s the future most tech analysts think (others think Web 3.0 is doomed to fail because blockchain is so little understood, adapted and even ironically – trusted – Crypto and NFT losses don’t help in this respect). Also energy use currently off the scale. That will need to change change and in some areas it is. Enough? No.
https://pre-sustainability.com/articles/blockchain-and-our-planet-why-such-high-energy-use
https://medium.com/luniehq/why-is-proof-of-stake-better-for-the-environment-8ac074721930

Bluesky will use something called Authenticated Transport Protocol (https://atproto.com/). Will it be subscription? Will it even be like Twitter? We don’t know. This is a bit more techy than my usual news but it matters not I suspect.
https://www.business2community.com/tech-news/jack-dorseys-bluesky-decentralized-social-media-app-will-not-be-blockchain-based-02565395

I am on Mastodon @AndyStroud@mastodon.online. I can see a few I follow on Twitter are there and they are also still on Twitter in the main (not all). Instagram might see some migrations. But frequent posters will have you muting them probably.

Mass migration from Twitter is not happening. Only if it files for bankruptcy (unlikely). Some info here about how Mastodon works:
How to use Mastodon

BlueSky is perhaps of more interest down the line but has not seen by anyone yet. And there is POST, in it’s infancy but getting a lot of interest. It’s going to be a while before it’s going to be really good (Twitter took years) and that enough people will opt in. It’s much more like Twitter than Mastodon and will become increasingly so. They say they will keep out the bad people. Join the long waitlist if of interest –  https://post.news/?r=tdmaJ

I am on Post. Optimistic for now. Not on Twitter really but keeping zombie account.

Maybe Bluesky will help join the dots on the numerous platforms that are out there.

Web 3.0 is out there (a bit) but how long for widespread adoption for the web (5 years, 10 years, never? Probably not never). And on what scale? A lot of companies are perfectly happy with Web 2.0 and centralised databases and haven’t got the money, resources or interest to move away from that. Good luck explaining Blockchain, DApps, Smart Contracts and Venture Capitalists to someone who wants a small website. Adapt or die some say. The debate has been going on for years already. We’ll know when Web 3.0 is really here when we don’t even mention Blockchain. If that happens. I’ll be long retired. More here if of interest:
https://en.wikipedia.org/wiki/Web3