I have one question. Assuming that I use the Ubuntu One account on my GNOME Desktop and after making several appointments, I need to go out and take my laptop with me. If I synchronize my Ubuntu One account via GNOME on my Laptop, will the appointments I made on the Desktop appear on my laptop? I would love this feature!
At present, Ubuntu One is just the single sign-on system used by many Ubuntu and Canonical services. As an OpenID 2.0 identity provider, third party web sites can also use it as a way to authenticate users without those users revealing their password to the site.
Between 2009 and 2014, we did offer file sync and structured data sync services under the Ubuntu One brand, but those have been shut down. While the structured data sync could certainly have handled calendar data, I don’t think we ever wrote any integration code for that: it was mostly just contacts, Firefox bookarks, and Tomboy notes.
If you want to have a calendar synchronised between your laptop and desktop, the best option at the moment is probably to use the Google Calendar integration.