By eliminating the need to leave your keyboard, you can perform a number of actions so much quicker. These include navigation, message formatting, message management, and editing.
Navigation:
Space Bar – takes you to the next unread message
Home Button - takes you to the first message
End Button – takes you to the last message
Up and Down arrows – Navigate up and down the message list
Left and Right arrows – Switch from digest panel and wave panel
Ctrl+Space Bar While focus is on Wave Panel – mark all messages as read
Message Formatting:
Ctrl+G – Color selected text (bring up a popup window for inputing desired color)
Contributed by shamanstears 
October 2, 2009 
Tagged: Google