Even President Barack Obama took jabs at the Yankees this week, cementing the fact that everybody—except, of course, Yankee fans—hates the World Champions. But are they actually the most loathed team in baseball?

Contrary to popular belief, the Yankees are only the fifth-most despised team in the majors, according to an Internet algorithm built by Nielsen Co. that analyzes how people feel about certain things. This service typically uses various keywords to find out whether people have positive, negative or neutral reactions...