Onboard is Ubuntu's default virtual keyboard, that allows the user to benefit a full-fledged virtual keyboard, featuring full key set, number and function (such as F1, F2, F3, etc) buttons, etc, bundle of features contained into a desktop-integrated interface.
Onboard 0.98 has landed in Ubuntu 12.10, continuing its road towards further improvements, presenting itself as mainly an under-the-hood focused release.