If you are logged into gmail, then it will show you a preview of your unread mails. If you have zero unread mails, then it will just show a gmail icon in color. If you are logged out, or for some other reason it cannot connect to gmail, then it will display a gmail icon in black and white. Clicking on the speed dial takes to you gmail.com (if you're logged in, you go straight to your inbox, otherwise you go to the gmail login page)
This a beta version. I'll make more fixed and update later as well.