Selecting your circle\n\n Tweets sent to your circle will appear with a green badge underneath them. They can only be seen by those you've selected to be in your circle and cannot be Retweeted or shared.
People not in your Twitter Circle can't see who's in it. You can't edit your Twitter Circle tweets after posting. Your Twitter Circle members can't retweet your posts. Twitter allows you to choose between your Circle and followers each time you tweet.