From the official notification:
While we have been proud over the last few years to have brought together such a vibrant, active, and creative community, unfortunately we will be closing Write On’s doors on March 22. After this date, access to Write On will be unavailable.
Your Amazon.com account will not be affected by the closure of Write On. If you don’t have any content you wish to save, no further action is required on your part.
If you do have content you wish to save, we encourage you to download your posted and drafted stories by March 22.
It’s always sad to see a writing site go away. If you’re affected by the WriteOn closure, let us know where you’ll continue posting your serials!