Twitter working on subscription service called Twitter Blue

Twitter Blue is a subscription service that Twitter is working on that features a new function called Collections and an Undo Tweet button. Collections will let users save and organize their favourite tweets.

The Undo Tweet button will let users cancel tweets up to a few seconds after sending the message.

Twitter may bundle Scroll with Twitter Blue, which would remove ads from the subscriber's feed.

The service is still in development, so details may change before launch.