Unsubscribe Button on Gmail - NEW!!!

Prior to the Can SPAM act, email growth and spam was totally out of control.
It seems like since then, there is usually an unsubscribe link hidden at the bottom of most emails.
There's also the mail handler's SPAM button which I guess makes all future emails from them go into the SPAM folder.

But this button is new on Gmail. It's not there all the time but when it is, it's cool:

Are all the emails handlers putting it there? Is it a generic new protocol? If so, I like it. Will everyone have to support it to be bulk emailer and not considered spammy at some point in the new year?