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.