Although Google Plus notifies you when someone adds you to their Circles, it doesn't inform you when you're being removed from them. Thankfully, a browser extension will fix this.
Similar to the Unfriend Finder extension for tracking friends who removed you from their Facebook’s friend list, GoogleMINUS is a browser extension that sends you live notifications when someone removes you from their Google Plus Circles.
To use the extension you have to install the Kynetx browser extension first. Kynetx is a platform that allows developers to easily build cross-platform apps that run on multiple browsers, adding extra functionality to favorite websites like Facebook, Twitter, Google, YouTube and more. Once Kynetx is installed, you can install GoogleMINUS or any one of their dozens of apps.
The installation process is a pain, to be truthful. Not only you have to install the Kynetx extension, you also have to create an account on their site. Fortunately, you can authenticate via Facebook or Google to establish an account on Kynetx.com.
Once the extension is in place and you are logged into your Google Plus account, GoogleMINUS will check the list of people who have added you to their circles, if anyone is no longer in that list GoogleMINUS will let you know through a pop-up alert.
Everything is not so rosy. Some users have reported that the extension doesn’t work. I don’t know if it does. You have to find that out yourself.
The extension is available for Google Chrome, Firefox and Safari.