It appears Pinterest is becoming increasingly popular with spammers and hackers. I was recently invaded with a mystery board and pin along with multiple likes to others with the same content having been posted to mystery boards on their sites.
They all appear to be from the same site stat,dealtime,com and have the same general content and photo.
This seems to be a large issue on Pinterest currently as it is the #1 help topic on the support page.
To resolve the issue follow the Pinterest support suggestions below:
If you notice boards, pins or other activity on your account that you did not create, it’s possible someone has gained access to your account.