A yelpmaniac is a person that has various accounts on yelp for trolling and flagging other members.
This person spends most of the day on the website, posting phony reviews and chatting on the boards.
Yelp maniacs steal photos from sites such as facebook for troll accounts.
Usually a huge drama king/queen.
Frederick G. is such a yelpmaniac that he sent private messages from 5 of his troll accounts today.