Go read it. It is actually shorter than his recent Facebook post on privacy.
This part was... umm, interesting?
Finally, regulation should guarantee the principle of data portability. If you share data with one service, you should be able to move it to another. This gives people choice and enables developers to innovate and compete.
This is important for the Internet — and for creating services people want. It’s why we built our development platform. True data portability should look more like the way people use our platform to sign into an app than the existing ways you can download an archive of your information. But this requires clear rules about who’s responsible for protecting information when it moves between services.
This also needs common standards, which is why we support a standard data transfer format and the open source Data Transfer Project.
This is pretty rich coming from him. Historically the options on Facebook to get your data have been terrible. But if there was a way to log into, say, Mastodon, connect it to Facebook and have all your data move over - that'd be pretty awesome (though I will not be holding my breath for anything like this).
I do agree that downloading a huge archive is not ideal and more services should offer ways to transfer information in and out of all platforms. It would be great if this were mandatory.
As I said in early March, this is a new phase for Facebook. It will be fascinating to watch.