The two-step verification is an optional feature that, when activated, requires a user to type in a numerical passcode when accessing a LinkedIn account from an unrecognized device. The passcode is sent via text message, and has to be entered each time a new device is used for the first time.
LinkedIn said in a blog post today that, "When enabled, two-step verification makes it more difficult for unauthorized users to access your account, requiring them to have both your password and access to your mobile phone."
The new security feature will also send an email to a user if the LinkedIn account has been accessed from a new device – so users can keep track of which devices have been authorized.
LinkedIn users can sign up for two-step verification by logging into their LinkedIn account and accessing the settings, selecting the "account" tab, and then clicking the "manage security settings" option.