Two-factor authentication is probably the best secure thing since passwords were invented. Two-factor authentication goes a long way towards protecting one’s accounts against being hacked. A password alone, no matter how long or secure, is no longer enough to provide sufficient protection. Social engineering, linked security breaches, leaked passwords and hacked mailboxes all contribute to the insecurity of password-based protection. Once the intruder gets ahold of someone’s password, they can access the account without a fuss. Worse even, they can work further to gain access to other accounts by e.g. using the hacked email address to request password resets on other connected services. Two-factor authentication aims to address this problem.
LinkedIn. Yahoo! Mail. Dropbox. Battle.net. IEEE. Adobe Connect. PayPal. eBay. Twitter. These are just a few recent examples of big name service providers being hacked, with literally millions of passwords leaked.