Google has released official Google+ web app for Chrome, which gives Google+ addicts to catch up their Google+ stream instantly with a single click.
If you are a heavy user of Google’s Google+ social networking product you are probably keeping the site running in a tab all the time to never miss new messages. But even if you do, you need to switch back to the tab regularly to see if there are any new notifications on Google+.
You can download Google+ app for chrome through Chrome web store.
Google+ Intro Video