@sophia On services like Twitter and Facebook users are required to have only _one_ single account (on Twitter multiple accounts is allowed, but you need to verify with phone number and you can't be logged in to multiple identities at once - as you can easily do on a federated network).

Facebook and Twitter offer no identity separation. Thus people feel the need to finetune, tweak and concentrate on using the _same_ identity in different situations. In a federated network that supports effective pseudonymity and near-anonymity (not requiring neither name nor phone number) your privacy is protected via identity separation. Different model, in my opinion better usability.