Twitter Adds Limited Two-Step Authentication
One by one, the major online services are all adding two-step verification. Twitter has just joined the crowd (including Apple and WordPress most recently) that has recently added the option for people to put a second verification step on their accounts. You can find this option on your settings page if it’s available to you, [...]
http://www.intego.com/mac-security-blog/twitter-adds-limited-two-step-authentication/