This is something I have been waiting for, well since I started using Gmail. I have tried the chrome plugins for notification but non of them really accomplished what I was really looking for. As soon as I saw the GMail blog post about these notifications I turned them on and I don’t think I would want to live without them again.
Rather than the small icon in the corner of the browser or the icon tray type notifications that have been done before GMail has used HTML 5 to provide us with true desktop notification. Already people have started posting negative comments about how you have to have GMail open for this to work but if you are like me GMail is always open anyway but I am often doing other things like working in Photoshop or writing code in Intype. When I am doing these things emails may be showing up but I would have no idea until I went back to that window, until now. Now while doing the actual productive things I use my computer for a nice big pop up appears int he lower left hand corner of the screen letting me know that the email arrived and I can click on this to see the email, simple and exactly what I wanted. This notification will also let you know if you get a chat. TO enable this feature just go to settings and scroll down a bit. You will be able to choose which types of messages you would like to be notified of email or chat and even more granular if you use priority inbox you can tell it to only notify you of important emails. For me this is my favorite GMail feature in a long time.
One other thing about the notifications is that you must be using Chrome as your browser but I have read that they plan on implementing this feature in Firefox version 4 and later. The reason for this seems to be the level of HTML 5 support so it would seem that eventually this feature will be available in all browsers.