Spam + Yelp = Spelp
When one person (or a group of people) join Yelp.com and make up bogus accounts just so they can review their own business favorably, or flag unfavorable reviews that legit Yelpers have written.
This term was derived by Boston Yelpers
Person 1: Did you see the reviews for <insert business name here>? Looks like a spelp to me, what do you think?
Person 2: Yea, one review, 5 stars, and doesn't say much. Total orange head too.
Person 1: Yea, I'm flagging it.
Person 2: Already on it.