Twitter on Thursday encouraged its more than 330 million users to change their passwords after the company discovered a bug that revealed the passwords in an unencrypted form in an internal log. Twitter said in a blog post that “we have no reason to believe password information ever left Twitter’s systems or was misused by anyone.” But the company urged users to take action “out of an abundance of caution.” In tweets Thursday afternoon, Twitter’s chief technology officer, Parag Agrawal, apologized for the error and said: “We are sharing this information to help people make an informed decision about their account security.