Tumblr on Monday added a very important security feature to its service, with the addition of two-factor authentication – an option available within the blogging service’s “Settings” section as of now. The move sees Tumblr at last joining the ranks of other top tech companies, including Facebook, Google, LinkedIn and Twitter, the majority of which offer some sort of two-factor authentication in order to provide an extra layer of security and protection for user accounts, making them safer from hacking attempts. Two-factor authentication, for those who don’t understand what that means, is a blanket term describing a method involving two stages (factors) for verifying a user’s identity. Simply put, it means you need two things in order to prove you are who you say you are – not just a username and password. One typical scenario would involve a user providing something they know, like a password, combined with something they have, like a cell phone tied to a verified phone number.