The phrase "ratings juggernaut" refers to something, such as a TV show or a sports event, that consistently attracts high numbers of viewers or receives incredibly high ratings. Full definition
Love it or hate it (though most seem to love it) this nerdy sitcom is a rare ratings juggernaut that ranks high in most social metrics. (canadianbusiness.com)
It coincides with the season premiere of the network's ratings juggernaut Game of Thrones on April 12. (canadianbusiness.com)
That's why I talked to Michael Hirst, the creator, writer, and executive producer of Vikings, the History Channel ratings juggernaut that starts its fourth season on November 30th. (inc.com)