Mark Zuckerberg set the world on fire Tuesday with the news that Facebook is working on something similar to a "dislike" button, but his comments were vague. Let's have Zuck speak for himself.
Speaking at a Q&A at Facebook headquarters Tuesday, Zuckerberg said he wants to give users different ways to express emotions other than the singular "like" button, but he doesn't want to turn Facebook into a "forum where people are voting up or down on people's posts." In other words, Zuckerberg doesn't want Facebook to become Reddit.
Facebook believes that its users want the ability to show "empathy," since in Zuckerberg's words: "Not every moment is a good moment."