Tumblr beefs up security with two-factor authentication
Just like you need two keys to launch a nuclear missile (and we really, really hope that you weren’t planning to do that anytime soon), you can now flip on the extra protection of needing-two-things to get at your Tumblr dashboard. 
Read more: Tumblr beefs up security with two-factor authentication
Story added 26. March 2014, content source with full text you can find at link above.