[orbifold]

I think two factor authentification is just an excuse to confirm your real identity, as it is much harder to obtain a fake phone number compared to a fake email address. I bet internally someone using two factor authentification is seen as more valuable to advertisers, since the phone number can probably be tied to a credit card record and other information collected by banks and other large real world companies. To 95% of twitter users it would probably be completely inconsequential if their account were compromised, just create a new one an let all your friends know.

[oddevan]

And to the last 5% that use the "Log in with Twitter" buttons in order to avoid creating another (probably weak) password, 2-factor is invaluable since it protects not just our twitter network but any accounts that it has been linked to.

[orbifold]

Sure if you don't care that Twitter knows all the services you use, then that is fine. It does make little sense to me to use Twitter as your main identity provider.