Twitter is experimenting with multi-factor authentication as a back up to the traditional user name and password that most experts agree is no longer sufficient to protect user accounts. Twitter has focused on the mobile phone as the keeper of the crown jewels for protection. Twitter’s new login verification feature will likely make it useful only to actors, politicians and other high-profile users willing to go through the hassle for tighter security. The number of malicious and high-risk Android apps rose to 718,000 in the second quarter of this year.”]