Yes, it’s not April’ Fool of 2014. Canonical has been confirm this new on their blog:
We are sorry to notify you that we will be shutting down the Ubuntu One file services, effective 1 June 2014. It is no longer possible to purchase storage or music from the Ubuntu One store. The Ubuntu One file services apps in the Ubuntu, Google, and Apple stores have been removed. As always, your content belongs to you. If you have already uploaded any content you can simply download your files onto your PC or an external hard drive. While the service will stop as of 1 June, you will have an additional two months (until 31 July 2014) to collect all of your content. After that date, all remaining content will be deleted.
Customers who have an active annual subscription will have their unused fees refunded.
Since April 2, it is no longer possible to purchase music files through the web-based Ubuntu One Music Store, nor buy additional storage space. The announcement of the cloud service closure means that the upcoming release of Ubuntu 14.04 LTS will not ship with Ubuntu One features on the desktop — no web apps, sync indicator or Ubuntu One client will ship by default.
Ubuntu One Single Sign-on Service (the thing you use to login to the Ubuntu Software Center, Ubuntu Forums, etc), nor the Ubuntu one Payment Services (used for buying apps) will be affected by the change, says Silber.