What is retweet?
Retweet is basically a re-posting of a tweet already posted, so if you were navigating through twitter and you saw a tweet that you liked and want to share with your followers, you can just go to the twitter’s retweet option, click on it and the retweet will be posted on your profile. In other words this feature helps you and all the twitter community to quickly share that tweet that you liked with all of your followers.
Sometimes you can see an RT at the beginning of a tweet; some twitter users type this to indicate that they are re-posting someone else’s tweet. This way of retweeting is not an official twitter command or feature, but it does signify that they are quoting another user’s tweet.
You can always retweet your own old tweets or the tweets from other twitter users and it all looks like a normal tweet, the only difference is that the tweets appears with the author’s name and username next to it, the retweet icon under the tweet is highlighted.
If you see content from someone you do not follow in your timeline, look for the “retweeted by” info in the tweet, it means the retweeter should be someone you do follow.
If you want to see if something that you have posted has been retweeted, just go to your notifications tab, there you can see all activity related to your tweets, which includes what tweets have recently been retweeted and by whom.
When you want to retweet something you like but you can’t, see if the lock icon is next to a user’s name on their profile page or on their tweets, if the lock is there, it means their tweets are protected and you will not be able to retweet their content, but you can always retweet and quote your own tweets, even if your tweets are protected, but only people you have allowed to follow you will be able to view them.
You can see the protected tweets from an account you follow because that twitter user has accepted your follow request, but, because that user have chosen not to share their tweets publicly, their tweets cannot be retweeted by you or anyone else.