"Whoops, you already said that", if you see this message after you post a tweet, this is what it means. You have already posted a tweet with the exact same words. This is something that is not allowed on Twitter for the simple reason - it could be spam. Since many spammers and bots online tend to post the same message over and over. Twitter in their efforts to protect their uses does not allow the same person to post the same message twice. The same massage can be posted by other people but not the same user. The same message can be posted by different users and a good example would be people tweeting a blog or a website post that they found useful. This is a Twitter error creating status report and can be corrected easily.