Of course this raises quite a lot of questions from a e/privacy standpoint. Just flagging that, in practical terms, we would all probably save a lot of time by simply exporting/importing our contacts from one social network to another. What would "portability" actually enable for most users?

True + ensuring some degree of interoperability amongst them perhaps. For instance, given that not all of my X contacts are (yet) on Bluesky this would be an initial limitation, unless the imported list can be automatically updated as other contacts register with the destination network.

True – and these are valid points, of course. Just wondering about the possible and more practical application to an otherwise rather ethereal (?) privacy right.