José Adorno, 9to5Mac:

Today, researcher Jane Manchun Wong said the service is going to be called Twitter Blue and, as for now, is priced at $2.99/month.

And:

Twitter Blue will feature a new function called ‘Collections’ which will let users save and organize their favorite tweets into collections to easily find them later.

And, on “Undo Tweet”:

This feature looks a lot like Gmail’s “undo send” button. The app just waits a few seconds before actually sending the message, so this could be what Twitter is planning to launch. As Wong shows, the company is working on the ability to adjust the duration of the undo Tweet timer from 5 seconds to up to 30 seconds.

More detail in the headline linked post. Note that “undo send” is not the same as an edit button. I use Gmail’s undo a fair amount, it’s definitely useful, but only when you realize a mistake/issue within a few seconds of clicking send.

I wonder if you’ll automatically get the blue checkmark if you subscribe, since it is supposed to be about being a verified account.