Just one bit. Are you proudly developing this only for Chrome, or is that just a support limitation right now?
I ask this because you didn't write something along the lines of expecting it to be released elsewhere soon - you wrote "exclusively" for Chrome.
I ask this because I currently use Firefox most frequently (although I installed Chime on my Chrome installation to test it). It might be a bit of a market limitation later when you try to monetize this if you only develop on Chrome.
And also, do you have any plans to allow independent hackers to write in their own notifications? Will I be able to write in notifications for platforms too obscure or unpopular to make a mainstream update for?
EDIT: I forgot one thing. Would you consider doing this for desktop applications as well, like Growl on Mac?