FrankerZ is a popular chat icon in TwitchTV chat streams. Typing FrankerZ will post a dog face. This icon has become popular among the speedrunning community. People post FrankerZ to mean a joke, sarcasm, or just to post FrankerZ. There is also a popular song based of FrankerZ that consists of a lyrics that are 90% filled with the word "FrankerZ"
User 1: That jump was boss
Broadcaster: Totally FrankerZ
User 2: That jump was terrible, what are you talking about?