Today Twitter admitted that the company had made a serious security blunder: it had been storing unencrypted copies of passwords.
Twitter claims that it has now “fixed the bug” and that its investigation “shows no indication of breach or misuse by anyone”.
Twitter therefore suggests merely that you “consider changing your password”.
Please do change your password(s) as soon as possible. There is no information about how long passwords have been out there in plain text or whether hackers managed to harvest any of them.