Does Ubuntu One support KDE?
Ubuntu One has not developed a sync client for KDE. Our focus has been on the service foundations and a limited set of platforms (Ubuntu and some mobile platforms) so we don't have extra resources and skills to address the needs of the KDE community. We have, though, partnered with developers on other platforms to create Ubuntu One sync clients... with KDE leading the way.
Harald Sitter has generously donated his time to develop the Ubuntu One KDE sync client as a 2010 Google Summer of Code project. You can find more information about his desktop application from his blog and the Launchpad project page. Please help to test this application and report all bugs here.