I've been getting a fair number of messages recently from a company called Zorpia, telling me that my friends are sending me messages. I am invited to view these messages, but I have to either let them have my Facebook or Google account details. According to the posts that I've read on the net about this company what they then do is harvest all of your contacts, and use your name to send out emails to them inviting you to join as well. The site at the name and .com address (I'm not linking to them directly for the obvious reasons) looks like it's a legit social media website, but I would suggest steering clear of them. Also, I'd be inclined to ignore the offer to take you off their mailing list - it doesn't work and will just confirm your email address. The best that you can do is to create a filter that automatically deletes their mails to you.
I don't normally issue alerts like this, but it seems to have got into the library/information community at the moment, so let's stop it before it takes hold!