The new option is billed as available for desktop, Android and iOS. Presumably, the rollout is gradual. This morning, I only saw the Twitter Blue subscribe button appear on my iPhone (it appears in the main menu).
The most-desired Twitter feature has to be the option to edit tweets, and get rid of that annoying typo or tag in someone you forgot.
Twitter Blue's headline feature, "Undo" offers that, to a fashion.
It throws up a preview of a tweet for a user-set period of between five and 60 seconds. While a countdown timer spins, you can make changes before the tweet goes live - or cancel it or save it as a draft.
Undo can be turned on or off for original tweets, plus the likes of replies, threads and polls
Twitter Blue users also get perks, namely the ability to:
• Customise the navigation bar (but there does not seem to be an option to always default to the latest tweets)
• Upload videos up to 10 minutes long (the great unwashed are restricted to two minutes and 20 seconds)
• Customise the look and feel of Twitter with more theme and text-size options
• Arrange bookmarks into folders
• Pin a direct message thread to the top of the DM interface
• Read ad-free articles from selected publications. Twitter says it has a list of publishers, but trying to find it threw me into a loop between Settings and Help. Promo material name-checks Reuters, The Washington Post, The Hollywood Reporter and Rolling Stone. You don't get access to paid content from a Twitter Blue partner.
Twitter Blue does not include an ad-free feed or priority support.
The new premium feature comes after Twitter made a loss in its third quarter - although the red ink was associated with a one-time charge to settle a lawsuit.
The company posted US$1.28 billion in revenue for the three months to September 30, with ad sales rising 41 per cent from the year-ago period.
So there is an edit button now? Oh, I only have 60 seconds to edit and I pay for it.
Unlike rivals Facebook and Google, Twitter was largely unscathed by Apple's new opt-in rules around ad tracking, due to the fact Twitter makes 85 per cent of its ad revenue from general, branded advertising rather than targetted ads.
The number of daily active users was up 13 per cent year-over-year to 211 million.
Twitter swung to a net loss of US$537m, from a net profit of US$29 m a year ago as the firm took a one-time charge of US$766m to settle a 2016 lawsuit that alleged the company misled shareholders.
Without the settlement, the company would have been on track for a US$229m profit.
Below: The three customisation options available through Twitter Blue, none of which really inspire $4.99 a month worth of buzz: