It's a major move for Twitter: The platform is finally caving to long-standing pleas from users and adding an edit button. As the New York Times snarks, it "has only been about 15 years, nine months, and 22 days since they started asking for that ability." Most tweeters, however, will have to wait awhile before being able to use what Twitter calls "Edit Tweet" in a blog post. The function will be tested internally first, then expanded to subscribers of Twitter Blue, who currently pay $5 a month for extra features. Twitter didn't say when, or if, the feature might be made available to its millions of regular users worldwide.