Facebook announced the launch of Libra just a couple of hours ago. And it’s very different from what was anticipated. The code is open source, transactions will be pseudo-anonymous and even though it is a permissioned blockchain to start, it is set to transition to permissionless over time. What’s the most important, though, is that Facebook will play very little role in governance. A new Facebook subsidiary, Calibri, will be one of the 100 validating nodes and won’t have more than 1% of the voting power.
So unless you use Facebook’s custodial wallet, and instead use one of the non-custodial wallets that will inevitably be developed, Facebook won’t know who you are or who you are transacting with. And that’s very similar to how other public cryptocurrencies currently function.