The HP logo is backlit with a multi colour LED. This LED is controllable via SMbus, though specifics are not yet known about controlling it as it requires further investigation.
It should be possible to make this LED, while in the OS, software controllable to change colour and blinking / no blink. This could be useful as a status indicator for various programs you might want to run.
This may be useful in finding out more:
Default LED Status Colours:
Blue: Ongoing activity.
Amber: Non-critical issue.
Red: Critical Issue.