The fake Twitter account, @ceoSteveJobs, has often confused thousands of Twitter users with its well written and timely updates. It managed to bag a whopping 650,000 followers. Earlier, Apple had filed a formal complaint of this parody account to Twitter in Jan 2011.
Twitter acted against the 'Steve Jobs parody account' for violating its rules. Twitter clearly stated that parody accounts must incorporate a clear signal, which shows it as a fake or parody, directly in the username or inside the account.
It is expected that Twitter may soon act against similar fake accounts, which are still active in various forms.