News broke today that Twitter will officially support retweeting (abbreviated RT), both on Twitter.com and through the Twitter API, which is what all Twitter apps use to interact with the service. Although the screenshots gave most people the impression that this was a simple user interface update, it is a much bigger deal!
Many users reacted to this news saying they didn't see the point, or don't use Twitter.com and therefore already have one-click retweeting. But this tiny change will have a massive effect on how information spreads across the community.
Today, when someone retweets, it's just a copy of the message with the original username added as a courtesy. But with this API change, RTs will be explicitly linked back to the original post. In other words, people will be able to keep track of how many times their tweet is passed around, no matter how far it goes!
With this change, Twitter apps will be able to query the main database to see how many times a message has been retweeted, rather than scanning the entire public timeline and finding duplicate text amongst all who are posting content to Twitter.
You can see the recent Twitter API additions, accurately labeled "retweets to me," "retweets by me," and most importantly "retweets of me."
Read the initial story along with a more detailed explanation at Mashable.