Google Chrome Extension: Notification System, RSS Reader

I've created a simple RSS Reader extension for my blog, however, I was wondering how I could implement a notification system (like Google Reader Notifier + Gmail Notifier have). So, a little number would popup on the extension icon when a ne开发者_开发百科w post is available/unread.

How would I go around doing this?

You can do this with the chrome.browserAction.setBadgeText API.

Something like:

chrome.browserAction.setBadgeText({ text: '5' });