"The title of "troll" is given to the cruel users who’s only purpose is to attack other users. They do things such as giving all their answers a thumbs down, reporting them for violations for no reason, and other things including outright insulting them. Commonly, they are jealous of the successful people who use their time wisely and they want some empty revenge. They need more than one account so they can make it seem as more users are against the targeted user. And also so when Yahoo reviews the abuse reports, they will see the reports from several users. That will make them believe they actually did break the community guidelines."