'Twitter Blue' subscription may add 'undo' button to iOS app

Twitter will allow users to 'undo' mistakenly-posted tweets in its app as part of its upcoming 'Twitter Blue' subscription, a researcher has uncovered, with the $2.99-per-month service also potentially including other useful premium features.Twitter is a free service to practically all of its users, with advertisers providing the bulk of revenue. However, the microblogging site may soon give users extra features in exchange for a relatively small monthly fee.Uncovered by researcher Jane Manchun Wong, the subscription is believed to be called 'Twitter Blue,' and is tentatively priced at $2.99 per month. The price could change ahead of launch, though it probably won't grow that much higher in cost. Read more...