Bottom line: Twitter has formally announced a new subscription offering designed to give power users access to enhanced features and perks on top of the existing platform experience. Current users can rest assured, we're told, that the free version of Twitter is not going away, and never will.

Twitter Blue starts rolling out today in Canada and Australia priced at $3.49 CAD / $4.49 AUD per month. That will open your account up to features like bookmark folders, so you can better save and organize tweets, as well as reader mode that makes it easier to read through long threads.

Subscribers will also have access to customizable app icons for their device's home screen, color themes for the Twitter app and a customer support line exclusive to subscribers.

The biggest new feature, and the one that users have been requesting for years, is the undo button. As the name suggests, this option gives you up to 30 seconds to "unpublish" a tweet before it goes live on your timeline. This could be incredibly useful to correct typos, to add someone you forgot to tag, or if you simply have a last-second change of heart about a particular post.

Twitter said Blue's initial feature set was developed based on feedback from the community, and that more features and perks are being planned over time. No word yet on when the subscription service will start rolling out in the US or elsewhere.

Image credit Ink Drop