Now conversations/notes/comments on particular books made using Pulse are also part of that cloud, as are the things that sync through Reading Life. Pulse hasn't been released for the Touch, yet. Sharing annotations to Facebook also takes place in what could be called "the cloud", if by cloud, we mean anything that happens off-device, on servers not under our control.
See:
http://www.kobobooks.com/kobovox_readinglife for some basic information on these features (Vox) version.