Joining Google's growing list of Chrome toolbar buttons is the Google+ Notifications extension. With it, you can view your Google+ notifications, directly from your Chrome toolbar.
The Google+ Notifications extension for the Chrome browser puts a notification button on your toolbar with a count of unread updates. Clicking on the button brings up a list of recent notifications. You can also add comments, reply, or manage recent circle activity, right from the notification list.
Just install the Google+ Notifications extension and you're all set. It's a nice way to get your Google+ updates without having to leave your current browsing session or creating a new tab/window, just to check for updates.