@SUp3rN0va the second link I think explains it pretty well. But to add to that, Jack Dorsey is responsible for killing the early idea of Twitter being federated.
Let me say this again, Dorsey is the person who killed the early push inside Twitter (we are talking very early, when it really could have made the difference) to make Twitter a decentralized service. As in, like fedi is today.
And now he's going to bloviate about open source at FOSDEM?..