Recently I removed Google+ from my Google account. Unfortunately, people are still adding my account to their Google+ circles. (I had assumed they wouldn't be able to do that anymore.) Worse, I now get an email every time they do that. The email has tiny text saying "To change what emails Google+ sends to you, you can always manage email subscriptions on the settings page." with a link. When I click on the link, guess what happens? It goes straight to a "Join Google+" page with no way to turn off the emails (unless I rejoin Google+ I guess) :-(. It's odious.
I'm still getting emails from Linkedin too. These sites are like malaria, once you've had them they're incurable.