My Google account has been hit with a lot of spam emails, spam messages on hangouts, and spam circle invites on Google+ lately. It's gotten so bad that every time I wake up I find annoying messages in my Hangouts messenger, and I use it on my phone as my replacement for texting because the app is just better than the default messaging app. So I don't know if they have branched out through my circles and attacked anyone else, or tried to add you to circles but, I am just warning you now - be careful who you add, make sure they're a person and not trying to market you - there are way too many people that setup accounts here just for marketing purposes and they'll not hesitate for a second to use you for their attempt at making money without your permission. I've demanded in a public announcement for them not to use me, and all it did is bring more to me. Be careful.