Facebook is rolling out "Reactions" which will allow users to express emotions beyond just "liking" a post. The new reactions will include options to express love, haha, wow, sad, and angry. Facebook hopes this will provide a better way for users to engage with different types of content and stories that matter most to them. The additional data collected from reactions could provide advertisers with new insights into how audiences respond emotionally to different ads and content. This represents an opportunity for advertisers to better understand sentiment and create more relevant and effective advertising on Facebook.