So, do you think you have what it takes to be a black belt in Gmail? How about a Gmail Master?
Google has released a Gmail tips website that uses different skill levels of "ninjas" to describe your mastery of the functions that Gmail offers. This site can be found here and is quite useful. It describes how to use video chat in Gmail, keyboard shortcuts, how to sign out of your account remotely, and more.
Judging by their rankings, it looks like I am moving into Gmail Black Belt territory. Let us know where you rate by leaving us a comment and also your favorite Gmail feature. For some inspiration on your electronic kung fu journey, go here.