..what might turn out to be Google+’s real killer app isn’t a feature inside Google+. It’s the new black bar that sits atop every Google property including the Google.com search page and Gmail accounts. The bar replaces the old links to other Google services, putting your name in the far left corner, giving you one-click access to your Google+ profile. But the real key is that on the right side, you have a box that turns bright red when you have a notification from Google+. If someone has commented or reshared your post, or added you to a circle, the box lights up. When you click on it, a dropdown box appears — and in the case that someone has added you to a circle, you see their profile pic and with a single click add them to one — or more — of your circles, hide them or outright block them. When there is action in your stream, the notification bar includes info like “Charlie Bloom commented on your post, Andrea Michaels, Bitt, Charlie Bloom, and 2 others +1′d it, Andrea Michaels reshared it.” And even easier, if someone comments on a post you have made or comments after you do on someone else’s post, you can reply directly from the notification drop down window, without ever leaving the other Google page you are on.