I receive about one invitation a day from on of my contacts to sign up with http://www.playmobsterworld.com

The DM message is: Hey, I just added you to my Mafia family. You should accept my invitation! Click here: http://...

Does anyone can tell me what this site is all about. Does it help with twitter?
Also it looks like today this site is down.

Don't sign up! It hijacks your account and sends links via personal messages to your contacts without your permission.

That is what I thought. Thank you for the warning!