Spammers and Google+

I have a google+ account, but don’t check it very often. There seems to be a significant amount of noise on the feeds and trying to keep up with all the people who added me to circles was driving all the real mail out of my gmail inbox.
This morning I realized the noise just got louder. It seems spammers are buying very, very old lists scraped from usenet and inviting everyone on those lists to join them on Google+. Yup, an address of mine that has not been used in 7 or 8 years and is not very publicly associated with me got a Google+ invite from someone I’ve never heard of before.
I know there have been a lot of complaints about spammers abusing Google+. I thought it was possible, but I didn’t realize they were actually purchasing email lists to load into Google and spam people.